[HN Gopher] Ryanair flight landed at Manchester airport with six...
___________________________________________________________________
Ryanair flight landed at Manchester airport with six minutes of
fuel left
Author : mazokum
Score : 698 points
Date : 2025-10-10 15:11 UTC (1 days ago)
(HTM) web link (www.theguardian.com)
(TXT) w3m dump (www.theguardian.com)
| SoftTalker wrote:
| Between overworked, understaffed ATC and undertrained pilots, I'm
| expecting some major disasters in the coming years.
| cschmatzler wrote:
| This had nothing to do with any of that tho.
| SoftTalker wrote:
| Pilots are ultimately the ones who are responsible for when
| and where to land, when to divert, and how much fuel to take
| along.
| ItsBob wrote:
| In this case, they likely had adequate fuel for, the usual
| eventualities but the weather in Scotland was particularly
| bad that night across the whole country (source: I live
| near Prestwick airport).
|
| Either Edinburgh (on the east coast) or Prestwick (on the
| west coast) are ok (one or the other or both) but in this
| case neither was suitable so the nearest was Manchester -
| definitely an edge-case.
|
| I don't know how much fuel they had, or if they could've
| fitted any more on the plane but it was unusual
| circumstances.
|
| There was a military plane right behind it with the same
| issue that night too.
| Spare_account wrote:
| Were these pilots undertrained?
| doitLP wrote:
| Why? Is ATC a problem in other countries than the US? Are they
| also under training pilots? If anything RyanAir with its
| flamboyant history of cost cutting (CEO always threatening to
| charge for use of the onboard lavatory) seems a more likely
| source than the flying infrastructure itself.
| xnorswap wrote:
| Ryanair has a very good safety history, among the highest in
| the world.
|
| They make outrageous claims for publicity, and their customer
| experience is all about hidden extras and "gotcha" pricing,
| but I don't think they fuck around when it comes to safety.
|
| They know that with their reputation they would be sunk if
| they did have a major incident.
| intrasight wrote:
| So it's sunk? They just had a major incident.
| jacquesm wrote:
| Let's wait for the investigation results before coming to
| that conclusion.
| jakub_g wrote:
| It's both true that Ryanair has very good safety record,
| and that in the past there were incidents with them landing
| on low fuel.
|
| https://www.eurocockpit.eu/news/mayday-mayday-wins-over-
| ryan...
|
| > In 2012 and 2013 "Brandpunt Reporter" broadcasted a two
| episode TV investigation in which Ryanair pilots, speaking
| anonymously, raised concerns about the airline's fuel
| policies and company culture. The pilots revealed that the
| company may be exerting pressure on them to minimize the
| amount of fuel they take on board - a practice which limits
| significantly the fuel costs for the company but could
| jeopardise safety in certain circumstances. The direct
| reasons for this broadcast were 3 emergency landings of
| Ryanair aircraft in Valencia Spain on the 26 July 2012,
| within a short timeframe due to low fuel levels.
| stuartjohnson12 wrote:
| Closely followed by the ritual lampooning of some senior middle
| managers who by the fish-in-barrel method were discovered to
| not be doing very much.
| dghlsakjg wrote:
| What indication is there that our pilots are undertrained?
|
| I am just a PPL, and that was not an easy thing to accomplish
| (most pilots complete 50% more hours than required before they
| are able to pass that test), but my impression is that western
| training standards for commercial pilots are incredibly high,
| and the safety record seems to back that up.
| psunavy03 wrote:
| Internet vibes, basically.
| bombcar wrote:
| Its arguably _too_ high, constraining the supply of pilots,
| and the supply of well-paying jobs, resulting in things like
| Colgan Air Flight 3407.
| dghlsakjg wrote:
| In the US, I think that's probably true especially using
| hours as a proxy for training.
|
| The EU has shown us that you can safely have far fewer
| hours.
|
| As a pilot I do think that nothing replaces butt in seat,
| but I also think that 1500 hours of instructing/aerial
| surveying/hour building is well into the diminished
| marginal returns area.
| the_mitsuhiko wrote:
| One of the problems with modern internet discourse is there is
| an implicit assumption that the problem of one country is
| automatically the problem of another country.
| afavour wrote:
| Flights operate internationally?
| Twirrim wrote:
| Yes, between other countries without having to go via the
| US!
| bilekas wrote:
| Internationally yes, but Ryanair don't travel
| transatlantic.
| bendigedig wrote:
| I think that's just Americans tbh.
| bilekas wrote:
| > Between overworked, understaffed ATC and undertrained pilots,
| I'm expecting some major disasters in the coming years.
|
| Maybe in the US, but this story is based in Europe, each
| country maintains a regulated standard and there are no EU wide
| disruptions that have ever happened to the best of my
| knowledge. Also Ryanair don't travel transatlantic flights.
| jakub_g wrote:
| Three weeks ago in Nice, France it was a fraction of a second
| away from two A320s crashing [0] and possibly hundreds of
| deaths, similar to Tenerife disaster [1].
|
| Investigation is ongoing and many factors are at play (bad
| weather, extra work for ATC due to that, confusing lighting
| of runways etc) but also, from French media reports, there
| used to be 15 people per shift 5y ago in Nice ATC, now there
| are just 12, and traffic is higher.
|
| Many people left the profession during Covid and haven't been
| replaced.
|
| [0] https://avherald.com/h?article=52d656fd&opt=0
|
| [1] https://en.wikipedia.org/wiki/Tenerife_airport_disaster
| bilekas wrote:
| Mistakes and disasters happen, unfortunately the safety we
| have while flying today has been written in blood, but
| there is no major understaffed ATC and undertrained pilots
| in general as mentioned.
|
| 15 down to 12 in 5 years with more traffic is not out of
| the question with advancements in technology but of course,
| if there is a report that shows understaffing then
| absolutely it should be addressed straight away and it will
| be, by the French government.
| SoftTalker wrote:
| Ryanair does use low-hour fresh-out-of-training pilots
| though. Certainly not the only airline that does that either.
| mardifoufs wrote:
| I mean, the US also hasn't had any widespread waves of
| disruptions that led to incidents or flight problems. Same as
| the EU. American flights and airspace are usually safer too,
| statistically speaking.
| arp242 wrote:
| I've never heard of any of these problems with RyanAir. They
| treat you as less than cattle and generally their service is
| shit, but I'm not aware of RyanAir being unsafe.
|
| Actually, in a quick check it seems the total fatality count
| for RyanAir is zero, with only two (on-fatal) major incidents
| (2008, 2021). That's seems a pretty good track record
| considering the amount of flights they do.
| anonymousDan wrote:
| Yeah there's a lot of hatred of Ryanair given their somewhat
| pugnacious attitude. But as far as I know they don't mess
| around when it comes to safety.
| tyre wrote:
| Looks like they tried two attempts to land in Prestwick over two
| hours, then flew to Edinburgh and made one aborted landing, then
| finally went to Manchester.
|
| What a nerve wracking experience for those pilots. I wonder if on
| the final attempt they knew they had to force it down no matter
| what.
| simplicio wrote:
| Assuming it wasn't just luck, it seems impressive they managed
| to maximize their (landing attempts/fuel reserves) ratio like
| that.
| searedsteak wrote:
| It is a requirement [1] to land with 45 minutes of fuel
| remaining, if the pilots go under that, it is considered an
| incident. As soon as estimated landing fuel goes under the
| limit, the flight needs to declare an emergency (as was done
| in this case).
|
| [1]: https://www.ecfr.gov/current/title-14/chapter-I/subchapt
| er-F... is the US rule, EASA has a similar rule.
| jacquesm wrote:
| Exactly. This will have a lot of consequences.
| jacquesm wrote:
| They got within a hair of crashing, there is nothing
| impressive about this. 30 minutes, ok, you still get written
| up but this is cutting it _way_ too fine.
| maccard wrote:
| > this is cutting it way too fine.
|
| Either this is true, or this is why there's a 45 minute
| reserve requirement. There were three failed landing
| attempts in two airports prior to the successful landing,
| and they spent almost as much time attempting to land as
| the scheduled flight took.
|
| Seems like this was exactly the scenario it was designed
| for?
| jacquesm wrote:
| No, this is what should never happen. I wrote fuel
| estimation software for cargo 747's and the one thing I
| would have never ever wanted to read is that an airliner
| of the company I worked for had landed with too little
| fuel.
| MagicMoonlight wrote:
| Right but this is an emergency... they didn't plan to run
| out of fuel
| jacquesm wrote:
| Clearly, that's why it makes the news.
| 7952 wrote:
| Are there ever situations where running into the reserve
| would be a good trade off?
| jacquesm wrote:
| This one. The reserve is there in the same way that a
| crash barrier is there on the highway. You really don't
| ever want to use it, but when you do use it and it ends
| well you treat it just as seriously as though you would
| treat a crash.
| hshdhdhehd wrote:
| I would imagine 6 min fuel left was designed for
| something extreme. Maybe involving damage to aircraft
| limiting where it can land etc. Or extreme weather event
| such had high winds affecting all airports within 500
| miles.
| gosub100 wrote:
| About 5 years ago before ATC recordings became mainstay on
| YouTube, there was an American pilot that declared an emergency
| at JFK and very firmly said "we are turning back and landing
| NOW. Get the aircraft OFF all runways".
|
| He was low in fuel and also frustrated with Kennedy ATC because
| he declared "minimum fuel" earlier and was still getting
| vectored around. (I know "minimum fuel" is not an emergency and
| has a very precise meaning).
|
| They must have been very close to running out. But it was a
| valuable lesson learned in speaking up before you get to that
| point.
| Esophagus4 wrote:
| I'm guessing that pilot had also been taught the lesson of
| Avianca 052, which crashed at JFK because the FO / captain
| did not explicitly declare a fuel emergency.
|
| JFK ATC in particular has an enormous workload with many
| international flights, combined with direct, even conflictual
| at times, NY communication style. It puts the onus on the
| pilot for conveying the message to ATC, rather than ATC for
| extracting the message from the pilot.
| khuey wrote:
| You might be thinking of
| https://www.youtube.com/watch?v=-sQuHnrJu1I
|
| For comparison, this is what can happen when the pilots are
| not that assertive
| https://en.wikipedia.org/wiki/Avianca_Flight_052
| gosub100 wrote:
| this was it, thanks for finding it. I didn't realize it
| happened 14 years ago
| traceroute66 wrote:
| > But it was a valuable lesson learned in speaking up before
| you get to that point.
|
| I'm not sure it was a lesson learned per-se because the
| captain was merely doing his job as fundamentally defined.
|
| _A captain has ultimate responsibility for the aircraft_.
|
| However there is a side question in relation to your post...
|
| When you say "declared an emergency" in your post, the more
| interesting question would be whether it was actually
| formally declared by the captain (i.e. "MAYDAY") or whether
| the captain was merely "working with" ATC at a lower level,
| maybe "PAN" or maybe just informal "prioritised".
|
| If the captain _DID_ declare "MAYDAY" earlier in the
| timeframe then yes, Kennedy would have a lot to answer for if
| they were spending excessive time vectoring around.
|
| But if the captain did not formally declare and then came
| back later and started bossing Kennedy around, that would be
| a different set of questions, focused on the captain.
| vdqtp3 wrote:
| In the US, we don't typically call Mayday/PanPan (despite
| it being both allowable and more correct). Pilots literally
| say "N777DS declaring an emergency. Engine out/Low
| fuel/Birdstrike". The effect is that all emergencies are
| Mayday.
| aeronaut80 wrote:
| The word Mayday is not required to declare an emergency.
| Pan pan still indicates an emergency. And neither
| phraseology is required as long as the intent is clear, see
| https://www.faa.gov/air_traffic/publications/atpubs/atc_htm
| l...
|
| In fact, it doesn't even need to be the pilots who declare
| an emergency https://hsi.arc.nasa.gov/flightcognition/Publi
| cations/non_EA...
| traceroute66 wrote:
| > The word Mayday is not required to declare an
| emergency.
|
| That may be so in the US.
|
| But it is a bad habit to pick up.
|
| Especially if you are an airline pilot and you frequently
| fly to destinations where English is not the first
| language.
|
| Or indeed in US airspace where you frequently get
| international carriers flying in and out.
|
| There is a reason why there is internationally agreed
| standard phraseology for radio communications.
|
| Everyone learns MAYDAY/PAN and the associated
| expectations around it (e.g. radio silence etc. etc.)
|
| Not everybody will be able to adequately follow along if
| you have a long drawn-out waffle discussion over the
| radio ... _" we have a little problem"_ ... _" do you
| want to declare?"_ ... _" oh wait, standby ...."_ .... _"
| oh, we're ok for now"_ ... _" oh actually maybe this or
| that"_... yada yada yada.
|
| If its truly an emergency then cut the crap and use the
| standard phraseology and keep the communications terse.
| gosub100 wrote:
| someone further down found the incident [1] I was referring
| to. It was 14 years ago, not 5 as I had initially thought.
| Curious to hear your take on it. Pilot said "if you don't
| give me this runway, I'm going to declare an emergency..."
| which I don't think is the most helpful thing to say. But
| there were definitely many swiss-cheese holes lining up
| that day.
|
| 1. https://www.youtube.com/watch?v=-sQuHnrJu1I
| moralestapia wrote:
| Context: because of bad weather.
|
| But I'm truly surprised (in a bad way) people on the ground
| couldn't solve the situation earlier. The plane was in an
| emergency situation for _hours_ , wtf.
|
| Also, the airport density in the UK is high, they should have
| been diverted since before the first attempt, as it has
| happened to me and thousands of flights every single day around
| the world.
| dehrmann wrote:
| Armchair quarterbacking it, but it was human error. They
| should have diverted sooner and been more aware of the
| weather.
|
| Edit: there might also be part of Ryanair culture that
| contributed, but that's speculation.
| jacquesm wrote:
| That's one conclusion. But don't rule out a lot of other
| things that may have been a factor, for instance, they may
| have had a batch of bad fuel, they may have had less fuel
| to start with than they thought they had (this happens, it
| shouldn't but it does happen), the fuel indicators may have
| been off (you only know for sure after touch down), there
| may have been a leak, an engine may have been burning more
| than it should have. There are probably many others that I
| can't think of of the top off my head but there are a lot
| of reasons why the margins are as large as they are.
| dehrmann wrote:
| Those are all possibilities, but
|
| https://www.flightaware.com/live/flight/RYR3418/history/2
| 025...
|
| They had at least an extra hour of fuel, and they landed
| at the third airport they tried.
| jacquesm wrote:
| Yes, that's how it should be. Something went badly wrong
| here. The big question is what.
| krisoft wrote:
| I read and agree with all those options being possible.
| Except the "they may have had a batch of bad fuel". How
| would that work in your thinking? I can imagine a bad
| batch of fuel leading to engine damage or flameout and
| many other things, but it is hard for me to imagine how a
| bad batch would lead to not enough fuel remaining in the
| tank.
| jacquesm wrote:
| If you have more water in the fuel than you think you do
| (there always is some due to condensation in the tanks)
| then you might be able to reach your destination but
| you'll be burning more 'fuel' than your original estimate
| would have you believe because there is less power per
| unit weight of (contaminated) fuel.
|
| This is fairly common in GA and there are cases where it
| has happened in scheduled flights as well. That's why
| fuel sampling is common practice.
| krisoft wrote:
| Interesting. That makes sense. Thank you for the
| explanation!
| jacquesm wrote:
| It's supposed to be an extremely low amount and the fuel
| pick-ups are placed such that it should never be a
| problem but there have been cases where water in the fuel
| caused problems, including at least one notorious crash
| where the cause was identified to be fuel contamination.
| jacquesm wrote:
| The incident investigation will surely focus on exactly those
| things. But: just like shipping aviation is at the mercy of
| the weather and even though the rules (which are written in
| plenty of blood) try to anticipate all of the ways in which
| things go wrong there is a line beyond which you are at risk.
| I've had one triple go-around in my life and it soured me on
| flying for a long time afterwards because I have written
| software to compute the amount of fuel required for a flight
| and I know how thin the margins are once you fail that third
| time. I am not going to get ahead of the investigation and
| speculate but I can think of at least five ways in which this
| could have happened, and I'm mostly curious about whether the
| root cause is one of those five or something completely
| different. Note that until there is weight on the wheels you
| don't actually know how much fuel remains in the tanks, there
| always is some uncertainty, to the pilots it may well have
| looked as if the tanks were already empty while they were
| still flying the plane. Those people must have been extremely
| stressed out on that final attempt to land.
| lo0dot0 wrote:
| There must be measurements of the fuel tanks state, right?
| jacquesm wrote:
| There are but this is not as precise as you might think
| due to a lot of confounding factors. Even the best flow
| meters are only about 0.2% accurate, and I find that
| seriously impressive.
| volkl48 wrote:
| Per the FlightRadar24 logs, it looks like only about 45min was
| wasted over Prestwick, not 2hrs. First approach was around
| 18:06, and they're breaking off to head for Edinburgh by about
| 18:51.
|
| If there's considered to be a mistake here though, I'm guessing
| it's going to be spending too long before committing to the
| initial diversion.
|
| Without knowing the weather they were seeing at the time, seems
| hard to say if they should have gone for a closer 2nd alternate
| than Manchester.
| ibejoeb wrote:
| I don't think we know yet when min fuel was declared. At that
| point, they will be resequenced. Then we need to know when
| mayday fuel was declared. It sounds pretty odd, like perhaps
| there were multiple simultaneous situations and the crew did
| not have adequate information.
| bell-cot wrote:
| > The pilots had been taking passengers from Pisa in Italy to
| Prestwick in Scotland on Friday evening, but wind speeds of up to
| 100mph meant they were unable to land.
|
| > After three failed attempts to touch down, the pilots of
| Ryanair flight FR3418 issued a mayday emergency call and raced to
| Manchester, where the weather was calmer.
|
| #1 - if Prestwick had wind speeds up to 100mph, then why the h*ll
| was the airport not closed down?
|
| #2 - if the pilots had experienced conditions that dire during
| their first two landing attempts at Prestwick, then why the h*ll
| did they stick around for a third attempt?
|
| EDIT: The article's a big vague, but it seems to have been 2
| attempts at Prestwick, then 1 at Edinburgh, then the last-minute
| "oops, do I really want to die today?" decision to run to
| Manchester.
| Quillbert182 wrote:
| Looks like the third attempt was actually in Edinburgh
| closewith wrote:
| The third attempted landing was in their diversion airport,
| Edinburgh, not a third at Prestwick.
| TulliusCicero wrote:
| The third attempt was in Edinburgh, looks like.
| sleepyguy wrote:
| The plane landed with approx 67 gallons of fuel. They typically
| land with 670 gallons.
|
| A US gallon of Kerosene weights approx 6.5 lbs
| jacquesm wrote:
| That is _very_ exceptional. I 've written fuel estimation
| software for airliners (cargo, fortunately), and the number of
| rules regarding go-arounds, alternates and holding time resulted
| in there usually being quite a bit of fuel in the tanks on
| landing, by design. I've never heard of '6 minutes left' in
| practice where it wasn't a massive issue and the investigation
| into how this could have happened will make for interesting
| reading. A couple of notes: the wind and the time spent on the
| three go-arounds + what was necessary to get to the alternate may
| not be the whole story here, that's actually factored in before
| you even take off.
|
| I'd be very wary to get ahead of the investigation and make
| speculative statements on how this could have happened, the one
| thing that I know for sure is that it _shouldn 't_ have happened,
| no matter what.
| psunavy03 wrote:
| And the reason why those fuel reserves exist is to be a guard
| band allowing situations like this to happen without flames,
| wreckage, and death.
|
| Having worked with many US airline pilots over the years, this
| is also why they are so proud to be unionized. Sure, senior
| pilots make as much as some FAANG developers, but the union is
| also there so that management doesn't get bright ideas about
| things like cutting fuel reserves to cut costs without the
| union telling them to stuff it.
| jacquesm wrote:
| Management can't cut fuel reserves, not because the pilots
| are unionized but because there are some _very_ strict rules
| about these fuel estimations prior to take off and margins be
| damned. And those rules are exactly there because otherwise
| this kind of incident would happen far more frequently. But
| it 's regulation that is the backstop here, not the pilots.
| psunavy03 wrote:
| The point is that the unions are there to allow the pilots
| to advocate for all kinds of safety-of-flight related
| things like fuel reserves, crew rest, and so forth that
| management would be happy to cut to save money. And to do
| so without fear of retaliation.
|
| And if you don't think the airlines would love to lobby
| Congress about the regulatory backstop, well . . .
| jacquesm wrote:
| As I wrote elsewhere in this thread I actually wrote
| software to estimate the amount of fuel a jet should load
| to comply with the rules. This was commissioned by the
| airline and they were scared shitless that they would
| ever be found to be in breach of the regulations on this
| aspect. It is one of those red lines that you really do
| not wish to cross. There are other aspects of flight
| where you are right but this particular one is different.
|
| The main reason why airlines would like to take the least
| amount of fuel is because it immediately increases
| payload capacity and thus flight efficiency. This being a
| cut-throat market there is a serious incentive to cut it
| as fine as possible. So the regulations around this
| particular issue are incredibly strict: you have to have
| a certain amount of fuel left upon landing, you have to
| write up truthfully how much you still had left and you
| will be investigated without fail if you cut into the
| reserve. The good thing about unions here is that they
| help to make sure that pilots know they are safe
| reporting truthfully because the airlines can not
| retaliate if they would pressure the pilot to not report
| an incident (which all pilots would normally definitely
| do). So they're a factor, but it is the regulator that
| writes the rules here and they are super strict about
| this.
|
| And that's immediately why the calculation of the
| estimate becomes so important: you now have 30 minutes
| (or 45, depending) of deadweight + the deadweight for two
| alternates and an x amount of time in a holding pattern,
| plus up to three go-arounds. That really adds up, so you
| have to do your best to get the calculation as close as
| possible to what it will be in practice _without_ ever
| cutting into that reserve.
|
| It took me the better part of a year and massive amount
| of learning to write a small amount of code + associated
| tests to pass certification. It also taught me more about
| software engineering (as opposed to development) than
| anything I did up to that point in time and it made me
| very wary about our normal software development
| practices.
| in_cahoots wrote:
| As an aviation fan just reading this thread is quite eye-
| opening in terms of how much risk tolerance the average
| commenter has vs what is standard in the aviation
| community and on aviation forums. It's almost like
| peeking into two different worlds. I wonder if there
| would be any value in teaching an "engineering when lives
| are on the line" or "war stories from accident
| investigations" classes to new engineers. I feel like
| there's value in appreciating just how much more work
| goes into building a system where people's lives are at
| stake.
| auxiliarymoose wrote:
| Yeah it bothers me to no end with the
| "engineering"-inflation of various jobs.
|
| Like, I'm definitively not an engineer, nor does my day
| job really involve engineering, yet my title contains
| Engineer! I'm a proud CRUD monkey and designer.
|
| I have done engineering work previously when developing
| hardware, and it's really a different mindset (even in an
| agile & fast-moving engineering org). Safety, cost,
| reliability, multidisciplinary integration, etc. just
| don't really come up in a lot in web and app development
| (which is a wonderful thing, really--I love it!)
| sgjohnson wrote:
| The average commenter here is a software guy. I imagine
| for the average software guy a Master Caution would be
| like a minor compile-time warning, i.e. feel free to just
| disregard it. :)
| jjk7 wrote:
| I think the literal fear of death _might_ be motivation
| enough for pilots to advocate for safety? And if they
| want to fire you, would you want to work for them
| anyways?
| immibis wrote:
| The alternative to employment is death. Many people are
| willing to take a possible chance of dying to avert a
| certainty of dying.
| 12_throw_away wrote:
| > I think the literal fear of death _might_ be motivation
| enough for pilots to advocate for safety?
|
| You'd think, but individual humans are very very bad at
| estimating risk, and in toxic group and work situations,
| humans will often take on increased personal risk rather
| than risk conflict. I.e., they will value group
| conformity over their own safety ... especially if their
| paycheck is involved. Fear of death is not nearly as
| powerful as robust regulation and unions.
| oivey wrote:
| Famously, this fact is also why no one drives recklessly
| and no one has lost any limbs with power tools.
| jMyles wrote:
| ...that regulation is text in a database. It can be changed
| capriciously at any moment, like they often are.
|
| It takes people with ideas and a willingness to put
| pressure in the right places to be sure that sane policies
| prevail.
|
| I think it's pretty obvious that as time moves forward, we
| need to rely on "regulations" less. The root and history of
| the word in the political context is to make things
| regular. But state actions increasingly bring irregularity
| to the world.
|
| It seems absolutely fair to say that, in this situation,
| the people - the pilots in particular, but also cabin
| crews, ATCs, engineers, and their unions, are the backstop
| worth observing and celebrating.
| jacquesm wrote:
| If you land with less fuel than the legal minimum you are
| going to have a lot of explaining to do, there will be an
| investigation and you, the pilot _and_ the airline will
| get enough headache from it that you will make bloody
| sure it does not happen again. The pilot(s) may not be
| able to fly until that investigation has run its course,
| the airline may get fined or warned if this is the first
| time it happened. In an extreme case the pilots may lose
| their license.
|
| > It seems absolutely fair to say that, in this
| situation, the people - the pilots in particular, but
| also cabin crews, ATCs, engineers, and their unions, are
| the backstop worth observing and celebrating.
|
| I will hold off on that conclusion until the report is
| in. There are so many possible root causes here that
| speculation is completely useless, and celebrations would
| be premature.
| jMyles wrote:
| My apologies - I didn't mean to speculate about this
| incident in particular, but about the general role of so-
| called "regulation"; I thought it was unfair to minimize
| the role of the people and unions compared to the (in my
| view, comparatively flimsy) legislation.
| rcxdude wrote:
| I think the thing that's being pointed out as overlooked
| when praising the employees and the unions, is the
| _regulators_ , who are the people who play a very large
| part in making sure that the regulations are enforced.
| The regulations are just text in a database, but it's the
| regulators who actually make it happen. A pilot who wants
| to push back against a beancounter cutting corners has a
| union and a regulatory agency to back them up.
| yodelshady wrote:
| Regulations are paper. Who enforces the _behaviour_ , of
| whether to take off or not, on a windy night in central
| Italy?
|
| Of course the pilots are the backstop, and the unions are
| _theirs_ , so they can make necessary calls the money
| doesn't like.
| throwup238 wrote:
| The union is a nice backstop for issues around the edges
| that come up with corporate, but the real backstop is the
| pilots' licensing. By making them directly responsible
| for the plane as PIC, it gives them leverage over their
| employer that few other professions have. AIR-21 gives
| them significant protection from retaliation and the ASRS
| is confidential. ALPA helps them navigate that mess if it
| comes to it, but that's the real legal backing that
| pilots have.
|
| Same thing happens with Professional Engineers regardless
| of whether they are employed or work as independent
| consultants/firms. They're legally responsible for the
| bridges and other infrastructure they sign off on with
| laws protecting them from employers and clients.
|
| (I fully support the ALPA and other unions, I just don't
| think it plays as significant a role in following
| regulations as you claim)
| parineum wrote:
| > Sure, senior pilots make as much as some FAANG developers
|
| That's a funny way to phrase it. I'd probably go the other
| way and say "sure, FAANG developers make as much as some
| pilots..."
|
| Those pilots have hundreds of lives on the line every day.
| kroolik wrote:
| Those FAANG devs have milions of (social) lives on the
| line, though. Every day.
| kpmcc wrote:
| Is this a joke?
| jacquesm wrote:
| Yes. I think the average bus and train driver is completely
| underappreciated as well and they have a massive
| responsibility too. I know I could not do their jobs, it
| would weigh on me too much.
| abtinf wrote:
| Naively as an outsider, this situation seems like everything
| worked as intended?
|
| On a nominally 2h45m flight, they spent an _extra 2 hours_ in
| the air, presumably doing doing fuel intensive altitude
| changing maneuvers, and were eventually able to land safely
| with their reserves almost exhausted.
|
| I'm a little confused by what there is to investigate at all.
|
| How much fuel _should_ they have landed with?
| GLdRH wrote:
| 30min+
| jacquesm wrote:
| Yes, I believe this is correct for this model aircraft.
| fabian2k wrote:
| My understanding is that they shouldn't have spent that much
| time in the air (not intended as a guess for the cause). The
| margin is there for situations where you can't land earlier,
| not the margin for scheduling the landing. There is margin
| for expected potential delays, they were in the other margin
| that should never be used except in true emergencies.
| abtinf wrote:
| Oh I think I see; so is the question not "why did they land
| with so little fuel", but more like "why did it take so
| long to decide to redirect to a known-safe airport"?
| fabian2k wrote:
| I don't know. As the parent said, I'd be careful with
| guessing the root cause right now. They should not have
| been this low even if diverted due to weather.
| jacquesm wrote:
| Possibly. Or 'why did your fuel readings deviate from
| what was actually in the tanks' or 'why did we leave with
| less fuel than we thought we did' and so on. There are so
| many variables here speculation is completely pointless.
| All we know is that something went wrong, that it
| _almost_ led to a crash and that it involves an airline
| with a very good record when it comes to things like
| this.
|
| Low fuel happens, but this is (very) exceptional.
| wahnfrieden wrote:
| By asking such a question you understand the need for an
| investigation
| zerkten wrote:
| If they have to touch and go, how long would it take until
| they get the plane around for another approach? In fact, you
| might not get as far as that touch and go and have to go
| around. You need some margin for all of these eventualities.
| The likelihood is low that these happen, but they have to be
| accounted for.
| bluGill wrote:
| Sure, but the flight was a lot longer than planed. How much
| extra do we need. They declared an emergency, and thus put
| themselves at the front of the line. They had 6 more
| minutes to do that touch and go around if that happened,
| and since they were already in a low fuel emergency they
| get priority and so there is enough time to do that if they
| needed. (edit - as others have noted, 6 minutes with high
| error bars, so they could have only had 30 seconds left
| which is not enough)
|
| They landed safely, that is what is important. There is
| great cost to have extra fuel on board, you need enough,
| but it doesn't look to me like more was needed. Unless an
| investigation determines that this emergency would happen
| often on that route - even then it seems like they should
| have been told to land in France or someplace long before
| they got to their intended destination to discover landing
| was impossible.
| jacquesm wrote:
| > They had 6 more minutes to do that touch and go around
| if that happened
|
| 6 minutes is _way_ out of the comfort zone. They might
| not have made it in that case.
| scrumper wrote:
| Correct, article says they landed with 220kg which is
| around 6 minutes of _average_ fuel burn over an entire
| flight - bit less at cruise, a hell of a lot more at
| takeoff /climb.
|
| So I don't think 220kg is enough to do a go-around in a
| 737 (well, a go-around would've been initiated with a bit
| more than 220kg in the tank - they burned some taxing to
| the gate - but you get my point.) I've read around
| 2,300kg for takeoff and climb on a normal flight in a
| 737-8. A go-around is going to use close to that, it's a
| full power takeoff but a much shorter climb phase up to
| whatever procedure is set for the airport and then what
| ATC tells you.
|
| I just flew 172s but even with those little things we
| were told, your reserve is never to be used.
|
| These people came very, very close to a disaster.
| Fortunately they had as much luck left as they did fuel.
| bluGill wrote:
| I agree, well out of comfort zones. However to my reading
| multiple different things went wrong to get to this
| point.
| jacquesm wrote:
| That could be. We just don't know right now, but your
| intuition may well be correct, even if there is a single
| root cause there could very well be multiple contributory
| causes.
| bluGill wrote:
| They failed to land at two airports before the third. I
| can't say if they made the right decisions but that
| already is two failures.
| jacquesm wrote:
| Go arounds are _not_ failures.
| bluGill wrote:
| They are expected situations, but still a failure of the
| original plan.
| jacquesm wrote:
| They are not a failure of the original plan, they are a
| mandatory component of the original plan that if
| everything is nominal never gets executed. Every pilot on
| approach is ready for one or even more go-arounds and
| they happen quite frequently for a variety of reasons.
|
| They happen a few hundred times per day at ~100 k
| flights.
| behringer wrote:
| With 6 minutes left everyone could have died if
| _anything_ went wrong with the final landing, even a gust
| of wind could have ended everybody 's life.
| bluGill wrote:
| Could have, but pilots practice no fuel landings all the
| time (in simulators). If they can get to ground that is
| "level enough" nobody dies. It is not something you ever
| want to see in the real world (and in the real world
| people often do die when it happens), but it isn't
| automating people die.
| isaacdl wrote:
| I don't think that's all that true for airliners. Pilots
| definitely practice for engine-out scenarios during all
| levels of training up to the airlines, but the ability of
| a plane the size of a 737 to safely land on anything but
| a runway is...limited. And if you're low, slow, and
| trying to go around, that's not a lot of time to glide to
| ground that is "level enough".
| bluGill wrote:
| i didn't mean to imply no runway landings. Landing on
| grass is questionable. They would practice water landings
| though
| behringer wrote:
| Those landings are practiced from a reasonable altitude.
| ktallett wrote:
| Surely the issue is more that they decided to make so
| many attempts to land local. There should be a max level
| of attempts.
| jacquesm wrote:
| There is a lot of pressure on pilots to land local. But 3
| go-arounds happens, not often, but it does.
| ktallett wrote:
| Perhaps that decision needs to be removed from the
| airline and there needs to be an independent decision
| maker there.
| jacquesm wrote:
| Pilots are ultimately responsible for the aircraft,
| that's pretty much set in stone but if ATC would tell
| them to divert they would unless there already was an
| emergency.
| kqr wrote:
| There _is_ a max level, and it is three.
| stahtops wrote:
| How much extra do you need? Enough that a pilot/crew
| doing their job properly will never run out of fuel and
| crash.
|
| So yes they will do an "investigation". It's not a
| criminal investigation. It's to understand the
| circumstances, the choices, the procedures, and the
| execution that ended with a plane dangerously close to
| running out of fuel.
|
| This will determine if there were mistakes made, or the
| reserve formula needs to be adjusted, or both.
|
| Don't tell me about cost, just stop. Let MAGA-Air accept
| some plane deaths to have cheap fares.
| gregoriol wrote:
| Flight from Edinburgh to Manchester is just a bit more than 1
| hour, so after trying 2 landings, diverting to Edinburgh
| (15-20 minutes flight), 1 more landing attempt, well, you get
| very close to 2 hours.
| gsnedders wrote:
| I felt like that seems a little long from EDI to MAN (after
| all, EDI to LHR is typically a flight time of under an
| hour!), so:
|
| https://globe.adsbexchange.com/?icao=4d2256&lat=54.720&lon=
| -... is the track of this flight.
|
| Went around at EDI at about 19:10Z, landed at about 19:51Z,
| so about a 41 minute flight.
| gregoriol wrote:
| Right, I probably got the information for flight time as
| seen by a passenger on a ticket, not for a plane already
| flying. Thanks!
| paulddraper wrote:
| At what point should they investigate?
|
| 0 minutes?
|
| -1 minutes?
| jacquesm wrote:
| Anything less than 60 minutes would be looked at by the
| airline, anything less than the legally required amount (30
| minutes for a jet of this type iirc) will result in a very
| serious investigation. Note that for slower aircraft (for
| instance a turbo-prop) the time requirement goes _up_ not
| down because they may have to spend more time in the air to
| reach an alternate (or secondary alternate, if things are
| really bad, like what happened here).
| jenadine wrote:
| They should investigate after the first failed landing,
| regardless of the amount of fuel in the tank.
| jacquesm wrote:
| Go arounds are perfectly normal and are not a 'failed
| landing', a failed landing is a _crash_.
| metalman wrote:
| 6 min, is empty, 6 min is purely theoretical, 6 min would not
| clear for ground handling or a test start, or a fuel system
| check,6 min would not do a go around. will interesting to see
| if they release info about what the real amount of fuel left
| is, and an authorative discussion on how much useable flight
| time was there. did they actualy make the taxi to the
| terminal?, or run out on the apron?
| jacquesm wrote:
| Yes. There is another comment above making light of the 6
| minutes as if another go-around was still an option, that
| is a ridiculous take. They were going to bring that plane
| in and land it no matter what on this last run, otherwise
| they'd crash for sure. 6 minutes may not even be within the
| margin of readout.
| scrumper wrote:
| I think the article says that someone saw 220kg written on
| a log - that's about 6 minutes worth at cruise. So yeah,
| it's zero basically.
| jenadine wrote:
| By your logic you need an infinite amount of fuel.
|
| If you define X the amount of fuel you need after you land.
|
| And you say that X needs to be enough to make an emergency
| landing.
|
| And we define that the amount of fuel required for an
| emergency landing should cover the amount required for the
| landing operation while still having X in the tank when
| landed.
|
| X > X + landing_cost
|
| The plane already had made 3 failed attempt before and was
| redirected to two different airports.
| gsnedders wrote:
| As others have said, final fuel reserves are typically at
| least half an hour, and you shouldn't really be cutting into
| them. What if their first approach into MAN had led to
| another go around?
|
| With a major storm heading north-easterly across the UK, the
| planning should have reasonably foreseen that an airport 56
| miles east may also be unavailable, and should've further
| diverted prior to that point.
|
| They likely used the majority of their final fuel reserve on
| the secondary diversion from EDI to MAN, presumably having
| planned to land at their alternate (EDI) around the time they
| reached the final fuel reserve.
|
| Any CAA report into this, if there is one produced, is going
| to be interesting, because there's multiple people having
| made multiple decisions that led to this.
| jacquesm wrote:
| Just reaching altitude again to make it to the first and
| later second alternate are mostly likely the biggest
| factors in the extra fuel consumption. That's very
| expensive.
| dTal wrote:
| You get that energy back on descent, no?
| bagels wrote:
| Some of it, but much is lost to drag. They do have to
| limit speed at all times.
| tamcap wrote:
| Not really. While you have a large potential energy
| buildup at a higher altitude, you cannot "bank it" /
| "save it" on descent. There is no way to store it in
| batteries or convert it back into fuel.
|
| One of the challenges of aeronautics is the efficient
| disposition of the potential energy without converting it
| all into kinetic energy (ie speed) so that the landing
| happens at an optimally low speed - thus giving you a
| chance to brake and slow down at the end.
| Reason077 wrote:
| > _" While you have a large potential energy buildup at a
| higher altitude, you cannot "bank it" / "save it" on
| descent. There is no way to store it in batteries or
| convert it back into fuel."_
|
| An electric fan aircraft absolutely can recharge it's
| batteries on descent. The fans simply act as turbines,
| creating drag to slow the aircraft and electricity to
| charge the batteries. Large commercial airliners already
| have a small turbine that works this way, the Ram Air
| Turbine (RAT) which is used to generate electrical power
| in emergencies.
| tamcap wrote:
| You can use a turbine to generate electricity, so yes,
| you are converting potential energy into electrical
| potential. However, no real mass produced passenger plane
| today can use that electricity for flight (thrust).
|
| RAT is only used when sh*t hits the fan. Even then, it
| can help you power some hydraulics / electrical, not
| "store" energy for further flight.
|
| The OP asked - in a low fuel situation, can the energy
| spent on a climb get effectively recovered - and the
| answer is not really. We convert as much as we can into
| unpowered (low-powered) descent. But once you are at a
| spot where you make a final decision to land or not, you
| are by design low and slow - and all that energy you had
| 15m ago is gone.
|
| If you need to keep flying, those engines need to spool
| back up. And that takes fuel.
| rkomorn wrote:
| > RAT is only used when sh*t hits the fan.
|
| Isn't it when air hits the fan, technically?
|
| (Sorry.)
| epcoa wrote:
| How? On descent you can trade some of your altitude
| (potential energy) for kinetic energy, but then you can't
| land the plane. For descent on an approach you're going
| from low energy to even lower energy. In emergencies and
| with enough runway you can futz around with this some,
| but wiggle room on an airliner is not great, negligible
| to what will be expended on a go around.
| recursive wrote:
| As someone who has ridden a bike up a big hill, and then
| down it, I don't think you get it back.
| krisoft wrote:
| That is perplexing. Of course you get the potential
| energy back. It turns into kinetic energy as you descend.
| That is why you need not pedal downhill, and often even
| need to brake to prevent the bike from speeding up too
| dangerously.
| anonymars wrote:
| > often even need to brake to prevent the bike from
| speeding up too dangerously.
|
| Indeed, which is what the airplane would have done on its
| way down to land. So it's more like riding the brakes on
| your way down the hill, and now at the bottom when you
| realize you need to abort the landing, you are at low
| speed and it's quite an exercise to get back uphill to
| try again
| howard941 wrote:
| The glider guys would always suggest a forward slip. It's
| a lot of fun to do. It's not taught often enough during
| primary training for powered airplanes.
| anonymars wrote:
| Yes, but that also doesn't get any energy back on
| descent, quite the opposite, that is "riding the brakes
| on your way down"
| kqr wrote:
| Aren't low-speed slips something that makes planes flip
| upside-down when not used very carefully? (Inadvertent
| rudder changes corrected with opposite aileron resulting
| in a snap roll.)
| vdqtp3 wrote:
| A cross controlled stall can result in a spin (which is
| probably what you mean by flip upside down). The rudder
| changes aren't inadvertent, they're intentionally
| opposite the aileron input - the goal is essentially to
| fly somewhat sideways, so the fuselage induces drag.
|
| In general forward slips are safe, but yes you have to
| make sure you keep the nose down/speed up. There's little
| in aviation that isn't dangerous if you aren't careful.
| anonymars wrote:
| You're probably thinking of a skid, which is when you put
| too much rudder in the _same_ direction as the ailerons.
| Then the lower (and slower because it 's on the inside)
| wing stalls first (and goes lower still) and away you go.
| Often when turning to land, so there's not enough
| altitude to recover.
| howard941 wrote:
| Yes, being that one is cross-controlled they must be used
| very carefully. It's really obvious that one is cross-
| controlling. It's the only time outside of really
| powerful crosswinds that you see what's below and ahead
| of you out of the side window. That view is what makes it
| fun.
| krisoft wrote:
| 100%. You are correct on that. You can't use your kinetic
| energy to go around after a landing attempt.
|
| But not because "you don't get the energy back". (As
| recursive suggested about a downhill bike ride which is
| the part i am disagreeing with.) You do get it back, but
| because you want to land you bleed it away to drag. And
| once it is bled away you don't have it anymore.
|
| So we don't disagree about the practical implications for
| flying. I'm disagreeing with recursive's particular
| statement about downhill cycling and what it implies
| about the physics of the problem.
| recursive wrote:
| Imagine a hill with 500 feet of elevation descent,
| followed immediately by 500 feet of ascent. No curves.
|
| If you coast all the way down the first part, you'll get
| about 20 feet up the other hill before you need to start
| pedaling. This is a direct analogy to "getting your
| energy back" by losing elevation.
| krisoft wrote:
| That is exactly what a rollercoaster does and it doesn't
| start "pedaling" after 20 feet. Of course real systems
| have losses and you can't practically use all the energy.
|
| But you don't have to believe me. Look at the video of
| this glider doing an unlicensed airshow:
| https://youtu.be/QwK9wu8Cxeo?si=L-0Mfmu8wk1ZlQU7
|
| It is a glider so it can't "pedal". You can see it
| steeply descending from 5:13 to 5:30 while it is speeding
| up and then the pilot picks up the nose and trades some
| of his speed for elevation again. And then he does it
| again around the 7 minutes mark.
|
| You have two buckets of "water". One bucket is kinetic
| energy and the other is potential energy. You can trade
| one for the other. You can also "lose" from the total
| volume of "water" due to drag (or friction in the case of
| the bike or roller coaster). Or you can add more "water"
| to your system by pedaling or thrusting with your
| engines. This is just simple physics 101. Also simple
| lived experience if you ever have the opportunity to fly
| an airplane.
| recursive wrote:
| The more water you put in your system the leakier your
| buckets get. Drag is not linear with speed. That was my
| point.
| PunchyHamster wrote:
| Just as with bikes, it will depend on how slow it is
| descending. On "right" trajectory engines could
| technically be basically idle, and you save fuel flying
| high so it might not be all that huge loss.
| Noumenon72 wrote:
| This is because bikes cost you about 50% more energy
| going uphill than walking[1]. You get back everything you
| don't lose from having to pedal too slowly, hunch over
| the front wheel, and maintain constant torque on the
| pedals.
|
| 1: https://pedalchile.com/blog/uphill
| robotresearcher wrote:
| No, and you don't want it. You want to be on the ground
| and stopped. In the lowest energy state.
|
| It's not currently feasible to harvest it into fuel. It's
| (very very nearly) all lost to drag, on purpose.
| MaxikCZ wrote:
| 4 replies and 3 are dismissing even the idea..
|
| Yes, you get "some" back, and its not negligible amount.
| Typical modern airliner can descend on 15-20:1, giving
| you over 150-200km (90-120mi) range from typical cruising
| altitude of 33 000 feet even with engines off. Most
| everyday descents are actually done by maintaining
| altitude as long as possible, and then iddling the
| engines fully for as long as clearance allows. (Ofc you
| then use engines as you geat nearer, because its safer to
| be a little low when stabilizing on approach, than a
| little high)
|
| Thanks to turbofans(edited from turboprops) better
| efficiency + less drag at higher altitude its actually
| more fuel economical to command full thrust and gain
| altitude quickly, than slower climb, or maintaining
| altitude (which goes against our intuition from cars,
| where if you wanna get far, you never give full
| throttle).
|
| But theres still some drag, so you dont get everything
| back, so you generally want to avoid murking in low
| altitudes as long as possible. Full thrust repeatedly at
| lowest altitudes (from failed go arounds) is the least
| economical part of flight, so you want to avoid those if
| possible. But its true that the altitude you gain is
| equivalent to "banking" the energy, just not all of it.
| jacquesm wrote:
| (1) this was a jet, not a turboprop
|
| Edit: changed turbofan into turbprop, which is what I
| meant.
|
| (2) fuel burned stays burned, you don't 'get it back'
|
| (3) the altitude gained may have been adjusted to account
| for the low fuel situation
|
| (4) the winds are a major factor here, far larger than
| the fact that 'what goes up must come down', something
| that is already taken into account when computing the
| fuel reserve in the first place.
| FireBeyond wrote:
| 1 - a turbofan is a subset of jet engine, and there are
| no 738s running anything other than a turbofan.
|
| Actually, nothing in civil aviation that has a "jet
| engine" has used anything but a turbofan (or turboprop)
| since the early 70s with the exception of Concorde and
| some older business jets.
|
| (Turboprops are jet engines, too, to be precise, with the
| jet of exhaust gases powering the propeller.)
| devilbunny wrote:
| > Turboprops are jet engines
|
| They are certainly _turbine_ engines, but I thought
| "jet" was reserved for those engines that propel the
| vehicle solely by their exhaust stream and bypass air. I
| am willing to be told I'm wrong, though.
| mnw21cam wrote:
| Turbofans are by your own definition jet engines. It's
| just that the bypass air is much larger.
| devilbunny wrote:
| I think you meant turboprop there, but the distinction I
| notice is that one has all propulsive airflow inside the
| nacelle, and one does not.
| mnw21cam wrote:
| Agh. No, I meant turbofan, but I misread your post and
| actually completely agree with you - turboprobs are not
| jet engines.
| devilbunny wrote:
| Ha! It happens. Enjoy your weekend.
| connorlu wrote:
| The 737-800 uses CFM56-7 turbofan engines.
|
| [1] https://en.wikipedia.org/wiki/CFM_International_CFM56
| #CFM56-...
| alwa wrote:
| (1) The turbofan category of jet engine seems to inspire
| a lot of very pretty animated technical diagrams--here's
| one set from a German manufacturer [0]. Now if only we
| could convince Bartozs Ciechanowski to take on such a
| subject... [1]
|
| (2) I know glider pilots who fly without any fuel at all,
| once aloft... sounds not unlike the 150-200km glide range
| that @MaxikCZ mentions at idle from cruising altitude.
|
| [0] https://aeroreport.de/en/good-to-know/how-does-a-
| turbofan-en...
|
| [1] e.g. https://ciechanow.ski/airfoil/
| jacquesm wrote:
| Yes, sorry, meant to write turboprop.
| devilbunny wrote:
| Aircraft that are _designed_ as gliders are much lighter
| and thus have much longer glide range than aircraft that
| aren 't. They're so lightweight that they can climb on
| thermals. A 737 is not going to be able to do that, but a
| regular glider can't fly at 400 knots.
| MaxikCZ wrote:
| > thus have much longer glide range
|
| Im gonna be a little pedantic, but the weight has
| surprisingly small effect on glide range, actually none
| of the weight affect the range directly, its all from
| secondary effects.
|
| The glide is given mainly by drag and lift (so body and
| wing geometry), correlated to certain speed. The weight
| isnt in the equation at all. What weight does, is
| increases the speed in which the aircraft achieves this
| maximum glide ratio, and in higher speed you have higher
| drag, which finally reduces the range.
|
| Thats why many modern gliders have water tanks in wings,
| to increase the weight of the glider, moving planes speed
| of best glide ratio higher, allowing for more efficiency
| at higher speeds. Its worth it if the atmospheric
| condition provide strong lifts. Pilot can then dump the
| water in flight to reduce the wing load, allowing them to
| land with less speed, or just keep in the air longer as
| thermals get weaker in the afternoon/evening
|
| (source, I used to be a glider pilot)
| devilbunny wrote:
| You are, of course, correct, and thanks for clarifying.
| justsid wrote:
| It should also be noted that gliders have crazy aspect
| ratios. Airliner wings are designed for completely
| different flight envelopes than gliders, it's all a game
| of what you optimize for and what trade offs you are
| willing and/or required to make.
|
| But of course that doesn't mean that airliners can't
| glide well, the Gimly Glider and Air Transat flight come
| to mind. But gliders can definitely beat an airliner in
| terms of performance.
| johndubchak wrote:
| Regarding the turbofan and [0], above...if you're
| communicating to a non-engineer (me), how does the design
| get to the point of such complexity? I would love to
| learn the design story behind such an incredibly complex
| piece of machinery.
|
| I am being serious, if you cannot tell.
| Gibbon1 wrote:
| For the same thrust it's more efficient to accelerate a
| large mass of air a small amount than t accelerate a
| small mass of air a large amount. The fan is what gives
| you that.
|
| I rough guessed the cost of fuel over a 737's life as
| $150 million. Where the engines cost something around $30
| million. That pushes the engineering economics towards
| maximizing the engines efficiency.
|
| I'm suspicious that bypass ratio's for turbofans are
| close to maxed out. The diameter of the fan gets
| unwieldy. That was the design issue that the 737 Max was
| trying to get around. With bad results. Possible the
| future is hybrid designs with two engines and 4 or more
| electrically driven fans.
| throw_a_grenade wrote:
| Re: (2): There's a difference between sailplanes and
| gliders. Sailplanes are gliders that can "soar", i.e.
| gain altitude just from the air that is moving up for
| some reason. Your friends have licence that says
| ,,Sailplane Pilot Licence", not ,,Glider".
|
| The distinction is less pronounced nowadays, because
| there is no mondern aircraft designed as gliders-but-not-
| sailplanes, but historically there were planes that fit
| this niche, mostly military transport of WW1 and WW2
| vintage.
|
| Passenger jets (with engines turned off) are relatively
| decent gliders, but incapable of soaring. So no, you
| can't get more that about 20:1 glide ratio no matter how
| good is the weather (for sailplanes).
| db48x wrote:
| No, you don't magically get the fuel back. But you do get
| a lot of the _kinetic energy_ back, and that energy keeps
| you flying without having to burn yet more fuel. You burn
| a lot of fuel while climbing, but then hardly any at all
| while descending. And that descent might cover 100 miles
| across the ground.
| MaxikCZ wrote:
| 1) Yea, sorry, turbofan, not turboprop nor a jet.
|
| 2) It stays burned, but the energy is banked in potential
| energy of the aircraft, namely in a form of altitude. If
| you run out of fuel 5 feet above ground, you dont get to
| fly far. When you run out of fuel 35000 feet above
| ground, you can still choose where to land from multiple
| options.
|
| 3) huh? I dont get what you trying to say, but: Its
| always more economical to climb, and the faster the
| better. Ofc you cant climb too high when you intend to
| attempt to land in 5-10 mins, but nontheless, every feet
| gained is "banked", and the aircraft is more economical
| to run the higher you are.
|
| 4) I am not saying the winds arent a factor, and in no
| way I was arguing about how fuel reserves are calculated.
| My only claim is that: yes, by spending more fuel to gain
| altitude, you can then "glide" down almost for free
| later. Its not 1:1, because of constant losses like drag,
| but its being compensated by higher engine efficiency and
| less drag at altitude, that its always worth it to climb
| if you can.
|
| There was a flight that was low on fuel diverting to
| alternate between 2 islands. The pilot panicked and chose
| slower climb to intuitively save fuel. They had to ditch
| the plane in water because of it - if they initiated full
| climb, they would have made the jump.
| dotancohen wrote:
| > fuel burned stays burned, you don't 'get it back'
|
| The _it_ that they get back is not fuel, it 's energy.
| Maintaining flight is energy management. They are getting
| the gravitational potential energy back, which is
| converted to velocity on descent, or bled off in drag by
| slowly losing altitude while maintaining airspeed.
| jacquesm wrote:
| So it seems. But because you want to land you then want
| to shed all that velocity. So you 'get it back' only to
| have to waste the bigger fraction of it. A go around is
| much like a mini take-off, you just miss the runway
| portion of it.
| MaxikCZ wrote:
| Nah. You want to land, but you are really not shedding
| most of your velocity until after touchdown. What you
| gain by burning fuel is energy, and you can either bank
| it into altitude, or velocity. You must shed both to
| land, but not so for go-around. There you shed almost all
| of your altitude, but you keep most of your velocity ->
| you still have a lot of energy left. That's why on go-
| around you spool your engines and start climbing
| basically right away, unlike typical takeoff, where after
| spooling up the engines you are still earth-bound until
| you build enough velocity.
|
| So you only ever really lost your "altitude" component of
| energy, not "velocity" one. You run your engines at TOGA
| (Take Off / Go Around = maximum thrust), thrust to gain
| mainly altitude, only increasing speed a little bit. Then
| on another approach attempt you use both the altitude and
| excess velocity bank again.
|
| In flight, ~all your energy losses go to drag. Doesn't
| matter if you bank it into speed or altitude, both is
| exchanged to be at minimums (0 altitude above ground,
| lowest safe landing speed) at touchdown. If you produce
| extra energy in your engines, it has to go to either
| speed or altitude, which you then pull out again, usually
| by maintaining speed while lowering altitude while having
| engines at idle.
| mrguyorama wrote:
| Some of it. The air density is an important part of
| efficiency at higher altitudes, so every moment spent
| under like FL320 is wasted fuel.
|
| So the entire climb "up", you are also wasting energy
| fighting the thick air. On the way back "down", that air
| again fights you, even though you are basically at idle
| thrust.
|
| Your fuel reserves are calculated for cruise flight, so
| time spent doing low altitude flying is already at a
| disadvantage. "Two hours of reserves" is significantly
| less than that spent holding at a few thousand feet. Fuel
| efficiency while climbing is yet again dramatically worse
| csours wrote:
| Wow this has a lot of replies!
|
| Yes, you get a lot of the energy back, BUT there is a
| huge problem!
|
| Large airliners incur a LOT of additional drag to slow
| down while landing. Some of that is entirely intentional,
| some is less intentional.
|
| It is highly preferred to deploy the landing gear before
| touching down. Failure to do so may lead to a hard
| landing and additional paperwork, so airlines do not
| allow the captain to exercise their own discretion.
|
| Extending the flaps maintains lift at lower speed, and
| higher flap settings allow even lower speed. The highest
| flap setting generally also deploys leading edge slats.
|
| If the wheels of the airliner touch down and detect the
| weight of the plane then spoilers kill the lift of the
| wings, air brakes fully deploy, as well as thrust
| reversers.
|
| All of these things add drag, which uses up all that
| energy you've been converting.
|
| The upshot is that each landing attempt uses a LOT of
| energy, and you have to use fuel to replenish that energy
| after every attempt.
|
| In other words, yes you get it back, but only for one
| landing attempt.
| throwaway173738 wrote:
| The problem isn't getting the energy back, it's doing so
| more slowly than gravity. Planes are somewhat limited in
| their ability to glide.
| cpncrunch wrote:
| The 30 min reserve is on top of the fuel needed to reach
| the alternate and do a landing there, so only the flight
| to the second alternate, plus the 2nd and 3rd landings at
| the initial destination would have cut into the reserve.
| nostrademons wrote:
| With 100mph winds I could easily see the 30 min reserve
| being eaten up by the flight from Edinburgh to
| Manchester. It's 178 miles! It takes a good 15-20 minutes
| to cross that distance when flying normally, add ascent &
| descent time and the landing pattern and you're easily at
| 24 minutes.
|
| Edit: in other comments here, it seems like Edinburgh to
| Manchester is a 45 minute flight. So yeah, they could
| easily have been outside of reserves when they did the
| go-around at Edinburgh and still had only 6 minutes left
| at Manchester.
| cpncrunch wrote:
| Yeah, although it depends what the alternate was in the
| flight plan. It may have been Manchester. Although I
| think its more likely it was Edinburgh, which in the
| circumstances was too optimistic. Too much concern about
| the minimal costs of fuel tankering to add a bit more
| gas? Or saving time by not refuelling?
|
| Ive never flown on Ryanair and dont intend to.
| jacquesm wrote:
| The flight plans I've seen accounted for _two_
| alternates, not one, a significant time in a holding
| pattern and up to three go-arounds. This was for cargo
| 747s and a while ago so chances are the regulations have
| changed by now, also, it may have been due to the kind of
| cargo.
| cpncrunch wrote:
| From what I can tell, that only seems to apply to EASA
| since 2022. As it took off from an EU airport and landed
| in the UK, I don't know if that rule would apply.
| lxgr wrote:
| As far as I've heard, Ryanair will cut into literally
| everything (including comfort and decency) for the sake
| of efficiency - other than safety. Even if they wanted
| to, they're subject to the same commercial aviation
| regulations as everybody else.
|
| Do you have anything other than this single incident to
| back up your insinuation that they're less safe than a
| full service airline?
| ifwinterco wrote:
| I don't know how true this is but I have heard Ryanair
| will use the absolute legal minimum amount of fuel
| whenever possible whereas other airlines might fly with a
| bit more.
|
| In theory though that shouldn't matter because as you
| say, the legal minimum should really be enough.
| lxgr wrote:
| That seems like a cost/convenience tradeoff: The
| implication of only carrying minimum fuel is that the
| pilots can't hold for long to see if conditions improve
| and instead have to immediately go for the alternate
| destination airport.
|
| The consequence of that is everybody ending up in the
| wrong place, but not in an unsafe way.
| MBCook wrote:
| I thought a lot of airlines had rules to limit the number
| of attempts you could make at a single airfield in an
| attempt to prevent this exact kind of situation.
|
| It sounds to me like they tried harder at their intended
| destination than maybe they should have, followed by going
| to an alternate airport that probably wasn't a good choice
| in the first place, and then having to divert to the final
| airport where luckily they could land in time.
| heelix wrote:
| Suspect they were IFR. All your points stand. First time
| flying things with a jet engine, I was shocked how much
| more fuel gets burned at low altitude. It almost always
| works out better to max climb to altitude and descend than
| to fly low and level. On a small jet, things can get spicy
| fast when ATC route you around at 5000' for 15 minutes or
| so. Three aborted landings would gobble gas like crazy.
|
| SS 91.167 Fuel requirements for flight in IFR conditions.
|
| (a) No person may operate a civil aircraft in IFR
| conditions unless it carries enough fuel (considering
| weather reports and forecasts and weather conditions) to--
|
| (1) Complete the flight to the first airport of intended
| landing;
|
| (2) Except as provided in paragraph (b) of this section,
| fly from that airport to the alternate airport; and
|
| (3) Fly after that for 45 minutes at normal cruising speed
| mr_00ff00 wrote:
| Why does it burn fuel so fast?
| TZubiri wrote:
| My guess is higher air density means more wind
| resistance, which acts as negative forward acceleration.
| alterom wrote:
| Not just that. Jet engines are efficient at higher speeds
| because the exhaust of the jet engine is _fast_.
|
| If the plane is going fast as well, that exhaust is more
| or less _stationary_ relative to the ground. The engine
| works to exchange the position of the plane with the
| position of the air in front of it.
|
| If the plane is going slow, it's _accelerating the air
| backwards_. That 's where the work is going, making the
| engine less efficient.
|
| Think about it this way: if the jet airplane is tied to
| the ground, its engines are running at 0% efficiency,
| working hard to blow the air backwards. You wouldn't want
| to stand behind a jet engine when the plane is about to
| take off, when that's effectively the case.
|
| The same applies to propeller-driven planes, of course.
| But those can _vary the prop speed_ as well as _propeller
| pitch_ , having more control on how fast the air is being
| pushed backwards. This allows the engine to be efficient
| at a wider ranger of speeds, particularly, at the slower
| range.
|
| But the propeller has a limit of how fast it can push the
| air back. When the prop blades start reaching the speed
| of sound, weird shit starts happening [1]. So propeller-
| driven aircraft have a limit on speeds at which they can
| go efficiently.
|
| Jet engines (turbo _fans_ when it comes to airliners)
| trade off low efficiency at low speed / low altitude
| (where the airplane is spending a small percentage of
| flight time) for higher efficiency at high speed / high
| altitude.
|
| Variable pitch turbine fans[2] aim to address this
| tradeoff, but the tech has yet to catch on.
|
| [1] https://en.wikipedia.org/wiki/Republic_XF-84H_Thunder
| screech
|
| [2] https://en.wikipedia.org/wiki/Variable_pitch_fan
| minetest2048 wrote:
| That sounds like Oberth effect in rocketry, where the
| faster you go the more efficient your rocket be:
| https://en.wikipedia.org/wiki/Oberth_effect
| testaccount28 wrote:
| they have nothing to do with each other.
| vasco wrote:
| I think about it like this:
|
| Jet needs to suck air from front. If air is stopped,
| sucking is hard. If air is already being thrown at you,
| you don't even need to suck, just let it come in.
| LikeBeans wrote:
| So perhaps the differential air speed between the intake
| and exhaust is a big factor in the efficiency equation?
| The bigger the difference the more work is needed..
| drstrangecharm wrote:
| You are right that accelerating the air backwards more
| reduces efficiency but I think it should be mentioned
| that the jet engine has to accelerate the air backwards
| to do any work pushing the plane forward. Picking it up
| and setting it back down affects the air with a net force
| of zero and therefore the force pushing the plane forward
| is also zero.
| jama211 wrote:
| Variable pitch turbine fans sound very interesting!
| Perhaps in the future as tech improves and fuel
| efficiency incentives continue to increase.
| TZubiri wrote:
| So, newton's first law?
| raviolo wrote:
| They were most definitely IFR. Not because of the weather
| but because IFR is required above certain altitude 18,000
| ft in the U.S. and typically lower in Europe (depends on
| a country). Jets including small private jets are almost
| always on IFR. Airliners with passengers - always.
| tstrimple wrote:
| > As others have said, final fuel reserves are typically at
| least half an hour, and you shouldn't really be cutting
| into them.
|
| This is one of the multiple layers of defense that airlines
| employ. In theory, no one single failure should cause a
| major incident because of redundancies and planning.
| Airlines rely on the "Swiss-cheese" model of safety. Each
| layer has its own risks and "holes" but by layering enough
| layers together there should be no clear path between all
| of the layers. In theory this prevents major incidents and
| given the commercial airline's safety records I'd say it
| works pretty fucking well. Landing with minutes of fuel
| left _should be_ exceptional. But it also shouldn 't be
| fatal or a major risk due to the other layers of the
| system. ATC will move heaven and earth to land a plane low
| on fuel or with engine trouble safely. And everyone else in
| the system having 30+ minutes of extra fuel gives the space
| for this sort of emergency sorting.
|
| I think this also reflects on the "efficiency" that MBA
| types bring to companies that they ruin. If an MBA sees a
| dozen landings with an extra hour of fuel, their mind
| starts churning at saving money. Surely an hour of extra
| fuel is too much and just wasted. Wasted because every
| extra gallon of fuel you take off with is extra weight you
| have to carry throughout the flight. Surely things would be
| more efficient if we could make sure planes only carry
| enough fuel to make their trip with very minimal overhead.
| And when everything goes perfectly according to plan, these
| decisions work out fine. Money is saved. Bonuses are paid.
| But the inevitable always happens. That's why it's called
| inevitable. Lives are lost. Wrists are slapped. Some people
| at the bottom lose their jobs. The world moves on.
| jstummbillig wrote:
| Interesting. To me it does not really make sense to think
| in terms of fuel left because, no matter the reserves,
| there can always be a situation so unlikely, so outside the
| ordinary, that it will drain _all_ fuel reserves before you
| make it to the planned destination.
|
| I have no clue how else to think about it though.
| lwhi wrote:
| So maybe the thing we can improve is an understanding of
| likelihood?
|
| I.e. prevent the journey from occurring if weather
| conditions are likely to be adverse above a certain
| threshold?
| loverofhumanz wrote:
| _" I'm a little confused by what there is to investigate at
| all."_
|
| You're confused why they should investigate how everyone on
| that flight came within minutes of dying?
|
| Something about the fuel reserves, procedures, or execution
| was clearly flawed.
| nickff wrote:
| Fuel depletion is risky, but not _that_ risky; see the
| Gimli Glider for a case much more dangerous than this,
| which still worked out amazingly well.
|
| Edit: Here is the Wiki on incidents... https://en.wikipedia
| .org/wiki/Fuel_starvation_and_fuel_exhau...
| loverofhumanz wrote:
| Depends largely on the altitude when fuel runs out. If it
| runs out when they're at 4,000 ft and it's windy, it's
| probably game over.
| behringer wrote:
| And what happens if you're not at 40k feet when the fuel
| runs out?
| nickff wrote:
| Good thing that airliners spend so much time at altitude!
| MBCook wrote:
| Especially while making landing attempts?
| 5f3cfa1a wrote:
| Fuel depletion is _not that risky_ is an interesting
| take. But hey, it won Chapecoense its first and only Copa
| Sudamericana, so maybe it isn't that bad after all?
|
| https://en.wikipedia.org/wiki/LaMia_Flight_2933
| jacquesm wrote:
| Fuel depletion is _stupendously_ risky, it is one of the
| most risky things that can happen to a jet. The only
| things more dangerous are fire and control systems
| failure.
|
| The Gimli Glider was a case of many items of luck lining
| up.
| troupo wrote:
| You could've read at least the Wikipedia page on how
| miraculous Gimli Glider was.
|
| From "all engine failure is never expected and not
| covered in training" to "Pearson was an experienced
| glider pilot familiar with techniques rarely needed in
| commercial flights" to the amount of maneuvers they had
| to execute on a barely responding aircraft
| jacquesm wrote:
| Exactly, the takeaway from that saga is that extreme luck
| does happen, not that flying without fuel is perfectly
| safe.
| nickff wrote:
| They also happened to know about an old airport which was
| no longer active, but did not know about the concrete
| barrier in the middle.
| gmanley wrote:
| That example is so well known due to how exceptional it
| was, especially how the pilots handled it. Robert
| Pearson, the captain, was a very experienced glider
| pilot. That's something that not many commercial pilots
| have.
|
| There were also two factors in the landing, that allowed
| for this to happen. You're going to be coming in really
| fast for a landing, when gliding in a commercial jet, and
| you don't have access to your thrust reversers to slow it
| down. There was a repurposed runway, that they used to
| land, that just happened to have been used as a drag
| racing track and had a guard rail. They were able to slow
| down by scraping across that. It also just so happened
| the nose gear didn't deploy fully so scraping the nose of
| the plane against the ground also helped slow it down.
|
| Needless to say it was a bunch of very fortunate events
| that allowed it to not end in disaster. In any case I
| would consider it very risky.
| dreamcompiler wrote:
| And even with all that scraping damage they were able to
| fly the plane out, repair it, and put it back in service.
| Amazing.
| cibyr wrote:
| The "scraping helped slow it down" theory makes no sense
| to me. What do you think has a higher coefficient of
| friction - tire rubber on asphalt, metal on asphalt, or
| metal on metal?
| smaudet wrote:
| Don't forget the surface area of contact...
|
| Rubber likely grips much better than metal, however three
| wheels have massively lower surface area than the body of
| the plane, or even a small section of it like the head.
|
| Of course we don't land tireless for other reasons (metal
| transfers heat exceptionally well unlike rubber, paint
| doesn't survive high speed impact, and it tends to deform
| upon impact with anything, making any future flights
| unsafe), but the fastest way to slow down if you don't
| care about safety or comfort would probably be to land
| tireless, if you could introduce some rotational spin,
| that might be faster (more force directed in multiple
| directions).
|
| Also, on the note of "coefficient of friction", remember
| that this number is not just some innate property of a
| molecule - as the metal scratches the pavement and
| deforms, its coefficient of friction goes up as micro-
| deformities accrue.
| gmanley wrote:
| I would hesitate to chalk it up to just theory, given it
| was in the NTSB report and they don't really mess around
| with throwing baseless stuff around. I'd be interested to
| take another look at it. They likely go into the material
| science and physics behind this very thing. They're
| usually filled with gems.
|
| You also have to keep in mind, it wasn't just rubber
| against asphalt, it was rubber on a wheel that spins. I'm
| not sure if the front nose gear on a 767 has any brakes
| but even if it did, I can't imagine it would be
| sufficient at the speeds they were going.
| jacquesm wrote:
| They could have died. The nosewheel assembly being pushed
| up through the floor of the cockpit has killed more than
| one pilot.
| gmanley wrote:
| I mistyped, as this was Canada it wouldn't be the NTSB
| but the Canadian equivalent at the time: Canadian
| Aviation Safety Board. The report is a good read.
| anonymars wrote:
| You seem to be assuming those are "or" rather than "and"
| foofoo12 wrote:
| I know you're trolling, but for anyone that hasn't heard
| of Gimli Glider, look it up or watch a documentary on
| youtube. The stars definitely aligned to make that
| happen.
| cosmicgadget wrote:
| Although credit is due to fuel reserve policies considering
| they landed after two diversions and three go arounds.
| dzhiurgis wrote:
| And that's why people shouldn't trust the guardian.
| awjlogan wrote:
| Why not? It's a factual report stating that the AAIB has
| opened an investigation into a potentially dangerous
| incident. There's not any editorial bias evident. See
| other extensive comments as to why this is not just a
| case of "it landed, so what's the problem?".
| dzhiurgis wrote:
| Sensational headline completely missing the point.
| al_borland wrote:
| Or did it work as intended? The plane had multiple failed
| landing attempts, was re-routed, and had enough fuel to
| land safely. While no one wants to cut it this close, this
| was not a normal flight.
|
| I'm not an expert in this field, but it would seem that the
| weight of extra fuel would increase operating costs, so
| it's is effectively insurance. How much extra fuel should
| be carried to account for unplanned events like this, while
| not carrying so much that it becomes cost prohibitive.
| TZubiri wrote:
| I think the argument is that this is precisely the tail end
| of exceptional conditions overfueling is designed for. If
| it's typical to fill fuel for 4 hours on a 2 hour flight,
| and the flight took 4 hours. It seems like this is exactly
| why they overfuel to 4 hours. If this happens once every
| 100k flights, then it doesn't even beg the question of "why
| aren't we overfuelling to 4.5 hours".
|
| This is just clarifying the question from the perspective
| of an outsider.
|
| That said, an investigation would be pretty reasonable,
| even if only to confirm that the abornamlity were forces
| majeures
| jacquesm wrote:
| > If this happens once every 100k flights, then it
| doesn't even beg the question of "why aren't we
| overfuelling to 4.5 hours".
|
| - This does not happen once every 100k flights. That's
| _once per day_
|
| - If this were happening once every 100k flights we would
| be adding another half hour to the reserve tomorrow.
| kube-system wrote:
| I'm not an aviation expert, but generally in safety
| engineering, safety buffers are not simply calculated as
| [normal situation] * [safety factor], but [worst case
| scenario] * [safety factor]
|
| If you ever cut into your safety allowance, you've already
| fucked up. Your expected design criteria should account for
| all use cases, nominal or worst-case. The safety factor is
| there for safety, it is never intended to be used.
| jacquesm wrote:
| This is exactly how it is in this case. Any consumption of
| the fuel reserve would result in an investigation, this is
| a very extreme case and it may even result in a change in
| the rules depending on the root cause.
| tonyhart7 wrote:
| Yeah idk people debating about this, if this justifiable
| then its all gucci and world can learn from such
| experience
| appreciatorBus wrote:
| Yes, exactly. The day it's normal to eat into the allowance
| is the day we start seeing planes falling out of sky for
| lack of fuel again. The only way to prevent that is to
| treat 30 min of fuel as seriously as you would 0 minutes.
| abtinf wrote:
| This is really helpful and I think I understand now.
|
| The approach is basically "accounting for everything that
| might go wrong to the best of our experience, including
| problems arising from the complex interactions between the
| airplane and supporting ground systems and processes, this
| is how much fuel you need in the worst case scenario. And
| now lets add more to give us a cushion, and we will treat
| consumption of this last reserve as tantamount to a crash."
| adastra22 wrote:
| Precisely.
| lo0dot0 wrote:
| Yes. Similarly, safety needs to be there even after the
| aging of materials over product lifetime. So basically when
| aging is the only variable to be considered end of life
| date is the worst case scenario.
| constantcrying wrote:
| >I'm a little confused by what there is to investigate at
| all.
|
| One of the most important aspects of taking safety seriously
| is that you do not just investigate things which had an
| impact, but that you proactively investigate near misses (as
| was the case here) and even potential incidents.
|
| A plane with 6 minutes of fuel left is always a risk to every
| person on board and potentially others if an emergency
| landing becomes the only option.
| MadnessASAP wrote:
| Indeed that is the definition of a "aviation incident"
| where there was a _risk_ of injury or damage. If there is
| actual injury or damage it becomes an "accident".
|
| The investigations into incidents aren't usually
| particularly long or noteworthy and often the corrective
| action will be to brief X on dangers of Y, or some manner
| of bulletin distributed to operators.
| Ekaros wrote:
| Only issue I see is that should there have been stricter
| rules to diverting way earlier. If winds were such as to make
| landing harder. Would just directly going somewhere else been
| the correct choice to force.
| jacquesm wrote:
| This is likely one of the questions the investigation will
| focus on.
| MBCook wrote:
| It also sounds like they went to an alternate airport they
| probably shouldn't have bothered with.
| rob74 wrote:
| Well, if you know you're pretty low on fuel, you are
| likely to pick an airport where the weather is good,
| rather than risking three more missed approaches at a
| closer one where the weather is probably also bad.
|
| Of course, Manchester is also a Ryanair base. There are
| two Ryanair bases closer to Prestwick (Edinburgh and
| Newcastle), but maybe the weather was bad there too? If
| the fuel situation was so dire, questions might be asked
| during the investigation why they didn't pick a closer
| airport with good weather that wasn't a Ryanair base (if
| one existed), but ultimately it's the pilots' decision to
| fly a bit further to an airport they are familiar with,
| and second guessing them with the benefit of hindsight is
| probably not a good idea...
| manarth wrote:
| They made two attempts to land at Prestwick, then
| diverted to Edinburgh (which also had bad weather). After
| one attempt at Edinburgh, they then diverted to
| Manchester.
| immibis wrote:
| Whether it can be prevented in the future. Should planes fly
| with _even more_ reserve fuel? It 's possible. Or maybe
| different ways of selecting alternate landing sites?
|
| It may even be the answer is "no, everything went as well as
| it possibly could have, and adding more reserve fuel to every
| flight would be unacceptably wasteful, so oh well", but at a
| minimum they'll probably recommend even more fuel on certain
| flights into risky weather.
| rolph wrote:
| ideally, enough to divert to another airport, in the off
| chance something happens, like a pending emergency at point
| post.
| TheJoeMan wrote:
| I think a more insightful answer is how often is it
| acceptable for the reserves to actually be cut into. If this
| was happening often, then there's a likelihood of a future
| disaster. As it is there is 1 isolated case that still ended
| with a positive outcome. I think it almost adds support for
| the current reserve levels to be pretty dialed-in.
| baq wrote:
| The answer is 'never' as the reserves are only added for
| worse-than-worst case scenario, i.e. in this case something
| went literally unimaginably (as of then) wrong.
| jacquesm wrote:
| Officially: never. Unofficially, a minute or two would be
| cause for concern and the regulators would most likely be
| showing an interest. The airline may have a higher margin
| than the official one. This is exceptional, they were
| within the margin of error on readout and the pilots must
| have known that. It's one thing to know you have half an
| hour of fuel give-or-take in the tank it is another to know
| that give-or-take you are running on fumes.
| wat10000 wrote:
| Imagine you're standing on a balcony and discover that the
| supports are cracked almost all the way through.
|
| Do you shrug and say, that's why they have a safety factor,
| everything worked as intended? Or do you say, holy crap, I
| nearly died, how did this happen?
|
| The purpose of the safety factor is to save you if things go
| badly wrong. The fact that it did its job doesn't mean things
| didn't go badly wrong. If you don't address what happened
| then you no longer have a safety factor.
| lazide wrote:
| If you get shot, but had a bullet proof vest on, and hence
| didn't die, technically everything worked as intended.
|
| Personally, I'd still want to figure out why I got shot and
| work on making sure that didn't happen again.
|
| Especially if you basically got shot multiple times (for an
| analogy in this case).
| appreciatorBus wrote:
| Depends if our goal is to have zero aircraft crashes. If the
| goal is zero, then for any given parameter, you have to
| define a margin of safety well before crash territory and
| treat breaching that margin as seriously as if there had been
| a crash.
|
| Similarly planes are kept 5 nautical miles apart
| horizontally, and if they get closer than that, you guessed
| it - investigation. Ofc planes could come within inches and
| everyone could live, but if we normalize flying within
| inches, the we are also normalizing zero safety margin,
| turning small minor inevitable human failings into
| catastrophe death & destruction. As an example, planes
| communicate with ATC over the radio and are given explicit
| instructions - turn left 20 degrees, fly heading 140 etc.
| From time to time these instructions are misunderstood and
| have to be corrected. At 5nm separation everyone involved has
| plenty of time to notice that something was
| missed/garbled/misinterpreted etc and correct. At 1 inch
| separation, there's no such time. Any mistake is fatal, even
| though in theory you are safe when separated by 1 inch.
|
| TBC an investigation doesn't mean investigating the pilots in
| order to assign blame, it means investigating the entire
| aviation system that led up to the breach. The pilot's
| actions / inaction will certainly be part of that, but the
| goal is to ask, "How could this have been avoided, and ask
| how every part of the system that we have some control or
| influence over might have contributed to the outcome"
| henryfjordan wrote:
| We shouldn't aim for 0 crashes due to low fuel though. How
| many deaths does carrying around 3x fuel than what you
| reasonably need contribute to via extra pollution?
|
| We should aim for 1 every 10-100 years or something
| reasonable like that.
| appreciatorBus wrote:
| We should account for deaths from pollution, but if we
| are going to do that, we should be willing to do that for
| 99% of aviation fuel that has nothing to do with reserves
| & safety margins, in addition to fuel used to drive cars.
|
| Any regulation short of "carry infinite fuel" will be a
| trade-off, and entail some risk and anyone involved in
| setting these knows that. Zero may not be our actual
| target or even possible, but it is a useful aspiration to
| ensure that everyone is pulling in the right direction.
| hshdhdhehd wrote:
| We dont aim for 0. Zero means dont fly. one in every 100
| years globally for all flights would be very safe.
| vdqtp3 wrote:
| On the contrary - commercial aviation does aim for
| perfection.
| jacquesm wrote:
| At 3x the number of deaths would be 0 because there would
| be no more flights.
| rz2k wrote:
| This reminds of discussions following the Fukushima disaster
| where one commenter claimed that it wasn't a design flaw,
| because it was an extraordinary circumstance. I found this
| appalling, because I do not at all think that was the risk
| profile that was sold to the public; I think people believed
| that it _was_ supposed to be designed to safely survive
| 1000-year earthquakes and the tsunamis that they create.
|
| Likewise, I think that the flying public is lead to believe
| fuel exhaustion is so rare that when airlines are compliant
| with regulations, no such disasters across all flights across
| all carriers will occur during your lifetime.
| philipallstar wrote:
| I'm sure we can all remember at least one person in any
| situation who will say something we find memorably awful.
| pornel wrote:
| It's also a communication problem, because labels like
| "100-year/1000-year event" are easily misunderstood.
|
| * they're derived from an estimated probability of the
| event (independently) happening _each_ year. It doesn 't
| mean that it won't happen for _n_ years. The probability is
| the same every year.
|
| * the probabilities are estimates, trying to predict
| extreme outliers. Usually from less than 100s of years of
| data, using sparse records that may have never recorded a
| single outlier.
|
| * years = 1/annual_probability ends up giving large time
| spans for small probabilities. It means that uncertainty
| between 0.00001% and 0.00002% looks "off by 500 years".
|
| https://practical.engineering/blog/2025/9/16/an-engineers-
| pe...
| kqr wrote:
| I find a useful exercise is to have a cheat sheet of
| historic flood heights in some area, tell someone the
| first record high, ask them how high they would make the
| levee and how long they think it would last. Peoples'
| sense for extremal events is bad.
| jacquesm wrote:
| That's a great exercise. Where I live a lot of people
| died because in the past we were not able to make that
| guess correctly. A lot was learned, at great expense.
| LightBug1 wrote:
| Really? Equally as an outsider - it feels like one "go-
| around" and you're fucked.
| sgjohnson wrote:
| If you cut into the final reserve, it's a full-blown
| emergency requiring a mayday call.
|
| This should not happen. So what's there to investigate? How
| it was allowed to happen, and how to prevent it from
| happening again.
|
| EDIT: it's a mayday even earlier than that. It's a mayday
| once the pilots know that they WILL land with less than the
| final reserve.
| jasonwatkinspdx wrote:
| > I'm a little confused by what there is to investigate at
| all.
|
| So because the safety margin still worked while down to near
| vapors we should conclude there's nothing to learn for the
| future to reduce the risk of similar incidents?
|
| That's certainly... a take.
| hshdhdhehd wrote:
| I dont know but maybe they should have diverted sooner. Maybe
| an hour into the flight?
| oxguy3 wrote:
| Well imagine they had to do a go-around on that landing. Go-
| arounds are extremely normal and might be done for a million
| reasons; your speed is wrong, your descent rate is wrong,
| your positioning is wrong, there's bad wind, there's an issue
| on the ground, etc etc etc. Six minutes of fuel is really not
| enough to be sure that you can do a go-around. So now, if ANY
| of those very normal everyday issues occurs, the pilot has to
| choose between two very bad options: doing a go-around with
| almost no fuel, or attempting a landing despite the issue.
| That's just way too close for comfort.
|
| Aviation operates on a Swiss cheese model; the idea is that
| you want many many layers of safety (slices of cheese).
| Inevitably, every layer will have some holes, but with enough
| layers, you should still be safe; there won't be a hole that
| goes all the way through. In this case, they basically got
| down to their very last slice of cheese; it was just luck
| that the last layer held.
| hugo1789 wrote:
| I think he would attempting a landing despite the issue in
| most cases because running out of fuel during go-around
| would be worse.
| hinkley wrote:
| One of those YouTube channels where a professional pilot
| evaluates flying incidents had a similar incident when the
| pilot started yelling at the tower when they tried to make
| him go around again. He essentially said he would declare an
| emergency if he didn't hear different instructions. I think
| he had 10-15 minutes when he touched down.
|
| One of the things the reserve is for is if the plane
| immediately in front of you fucks up the runway, you now have
| to divert to the next airport. You need at least enough fuel
| to get there and for the tower to shove everyone else out of
| the way so you can make an emergency landing.
|
| There are other reasons someone could abort a landing and
| have to go around again, besides debris in the runway. And
| sometimes two of them can happen consecutively.
|
| In the case I'm referencing, it was pointed out that p the
| pilot made things worse by going faster than he was told to
| fly, using up fuel and also making him too close to a
| previous plane which forced him to go around the previous
| time, so it wasn't all the tower.
| PunchyHamster wrote:
| Might not be about fuel but about why they even tried instead
| of diverting earlier.
|
| Might even be 100% done by the book but book needs changing
| (tho I doubt that, it's not exactly first case of "a lot of
| bad weather")
| jacquesm wrote:
| Our definition of 'bad weather' is definitely changing as
| we gather more data.
|
| Besides regular weather (which airliners aim to avoid
| except during take off and landing) there are many other
| factors at play here. There are several almanacs that are
| used for fuel calculations & navigation, they are updated
| annually.
|
| The fastest jet stream (the aviation equivalent of the
| trade winds) recorded is north of 400 Kph, having that with
| you, against you or perpendicular to your flight path will
| have a substantial influence on fuel consumption and flight
| duration.
|
| I agree with you that it may well end up with a regulatory
| change but that's one of many possible outcomes here. I
| will definitely keep an eye out for the report on this
| flight's investigation. It is going to make for very
| educational reading.
| goodcanadian wrote:
| _Naively as an outsider, this situation seems like everything
| worked as intended?_
|
| I don't remember all of the rules off the top of my head, but
| if you are _ever_ landing with less than 30 minutes of fuel,
| something has gone seriously wrong. You are required to take
| off with sufficient fuel to fly to your destination, hold for
| a period of time, attempt a landing, fly to your alternate,
| and land all with 30 minutes remaining. If you are ever in a
| situation where you may not meet these conditions, you are
| required to divert immediately. In choosing your alternate,
| you consider weather conditions along with many other
| factors. This was, without question, a serious emergency.
|
| From the very brief description in the article, I would say
| they should have diverted to Manchester at least 25 minutes
| sooner than they did. I will include the GP's caution,
| however:
|
| _I 'd be very wary to get ahead of the investigation and
| make speculative statements on how this could have happened,
| the one thing that I know for sure is that it shouldn't have
| happened, no matter what._
| hugh-avherald wrote:
| If you are ever in a situation where you estimate you will
| land with less than 30 minutes of fuel, you are _legally
| obliged to declare a MAYDAY_. One of the few situations
| where a mayday is legally required.
| nucleardog wrote:
| Thirty minutes.
|
| If at any point you expect to touch down at the nearest safe
| airport with less than 30 minutes of fuel remaining, you are
| required by regulation to make a mayday call.
|
| Mayday is a term enshrined in law. It is only to be used when
| people will die if you do not receive help. In the US,
| calling it inappropriately can be punished with up to 10
| years in jail and a $250k fine. It's protected in this way
| because as soon as you call mayday, in many situations there
| are actions that must be taken by law or regulation. Other
| appropriate uses include things like "our plane is on fire"
| or "our wing just fell off and we can't steer the plane".
|
| As soon as you think you can't land with the fuel reserves
| you are _required_ to call mayday, other pilots are
| _required_ to clear the radio for you, and ATC is _required_
| to provide any and all supported possible until you're on the
| ground.
|
| The investigation is not to figure out who to send to jail or
| something. The investigation is because a flight just came
| this >< close to having hundreds of people die. That fuel is
| there as a safety margin, yes. That's how everyone ended up
| walking off this plane instead of dying as the plane was
| ripped apart by some trees somewhere. That is good.
|
| But air travel did not become as safe as it with an attitude
| of "this hasn't killed anyone yet, all good". The fact there
| was an incursion into the safety margin should not be looked
| at as "eh, working as intended" but "holy hell we just came
| this close to disaster, what went wrong that almost killed
| all these people? how do we stop that happening again?". That
| is what an investigation will be looking to figure out.
|
| To put it in vaguely IT terms, this is something like... your
| application has started corrupting its database, but you have
| _a_ backup copy. On one hand, you can think "eh, we have a
| backup, that's what it's there for, who cares". On the other
| you can go "holy shit, any time we need to restore from the
| backup we narrowly averted disaster... how do we make sure
| we're not in that situation again?". The former is probably
| going to lead to irrecoverable data loss eventually. The
| second will have you addressing problems _before_ they ruin
| you.
| jenadine wrote:
| > If at any point you expect to touch down at the nearest
| safe airport with less than 30 minutes of fuel remaining,
| you are required by regulation to make a mayday call.
|
| From the article, they did issue a mayday call, when the
| closest airport was presumably Edinburgh. Then they flew to
| Manchester and landed.
| jacquesm wrote:
| There must have been a very good reason to do that.
| jacquesm wrote:
| What is fascinating about this whole discussion is that the
| general world of software development is so far away from
| actual engineering that all of these basics require
| painstaking explanation.
| kqr wrote:
| In safety-critical systems, we distinguish between
| _accidents_ (actual loss, e.g. lives, equipment, etc.) and
| _hazardous states_. The equation is
|
| hazardous state + environmental conditions = accident
|
| Since we can only control the system, and not its
| environment, we focus on preventing hazardous states, rather
| than accidents. If we can keep the system out of all
| hazardous states, we also avoid accidents. (Trying to prevent
| accidents while not paying attention to hazardous states
| amounts to relying on the environment always being on our
| side, and is bound to fail eventually.)
|
| One such hazardous state we have defined in aviation is "less
| than N minutes of fuel remaining when landing". If an
| aircraft lands with less than N minutes of fuel on board, it
| would only have taken bad environmental conditions to make it
| crash, rather than land. Thus we design commercial aviation
| so that planes always have N minutes of fuel remaining when
| landing. If they don't, that's a big deal: they've entered a
| hazardous state, and we never want to see that. (I don't
| remember if N is 30 or 45 or 60 but somewhere in that
| region.)
|
| For another example, one of my children loves playing around
| cliffs and rocks. Initially he was very keen on promising me
| that he wouldn't fall down. I explained the difference
| between accidents and hazardous states to him in childrens'
| terms, and he realised slowly that he cannot control whether
| or not he has an accident, so it's a bad idea to promise me
| that he won't have an accident. What he can control is
| whether or not bad environmental conditions lead to an
| accident, and he does that by keeping out of hazardous
| states. In this case, the hazardous state would be standing
| less than a child-height within a ledge when there is nobody
| below ready to catch. He can promise me to avoid that, and
| that satisfies me a lot more than a promise to not fall.
| jama211 wrote:
| Well said, will think about asking this attitude towards my
| child, seems very helpful
| jacquesm wrote:
| If you haven't done so: please write a book. Aim it towards
| software professionals in non-regulated industries. I
| promise to buy 50 to give to all of my software developing
| colleagues.
|
| As for 'N', for turboprops it is 45, for jets it is 30.
| edanm wrote:
| Seconded! This was an extremely well written and well
| thought out explanation of this idea. Would love to read
| more along these lines.
|
| (Will now be checking out your blog.)
| jacquesm wrote:
| Also check out risks digest:
|
| https://catless.ncl.ac.uk/Risks/
| xeonmc wrote:
| If he aims it toward five year olds as he had explained
| it, bet it would be even more applicable to our
| profession.
| abustamam wrote:
| Having spent some time with my five year old nieces and
| nephews, sometimes I wonder if five year olds could run
| companies better.
|
| (note: obviously sarcastic but kids really do have some
| amazing insights that we forget when trying to chase KPIs
| or revenue)
| DocTomoe wrote:
| Seconded.
|
| That being said: I have - for some years now - started to
| read air accident board reports (depending on your
| locale, they may be named slightly different). They make
| for a fascinating read, and they have made me approach
| debugging and postmortems in a more structured, more
| holistic way. They should be freely available on your
| transportation safety board websites (NTSB in America,
| BFU in Germany, ...)
| kqr wrote:
| I want to write more about this, but it has been a really
| difficult subject to structure. I gave up halfway through
| this article, for example, and never published it - I
| didn't even get around to editing it, so it's mostly bad
| stream of consciousness stuff:
| https://entropicthoughts.com/root-cause-analysis-youre-
| doing...
|
| I intend to come back to it some day, but I do not think
| that day is today.
| sans_souse wrote:
| Just started reading the linked text after reading your
| comment and I agree, this is high quality education, and
| enjoyable. It's an art, really. Thank you for sharing
| your work and please keep it up.
|
| Just a thought I had while reading your introduction:
| this is applicable even to running a successful business
| model. I'm honestly having trouble even putting it into
| words, but you have my analytical mind going now at a
| very late hour... Thanks!
| ta988 wrote:
| Thanks, I would buy your book. But I understand the
| effort necessary all too well.
| hengheng wrote:
| Write it as a children's book. A literal ELI5.
|
| (Knowing, of course, that it will still be read mainly by
| engineers. But that's the charm.)
| MandieD wrote:
| I have a rather over-confident five year old, so would
| LOVE that book right now.
| jacquesm wrote:
| Ok. I am impressed with your ability to take such complex
| subjects and make them plain, you are delivering very
| high quality here. The subject is absolutely underserved
| in the industry as far as I'm aware of it, and I would
| love to have a book that I can hand out to people working
| on software in critical infrastructure and life sciences
| that gets them up to speed. The annoying thing is that
| software skills are values much higher than the ability
| to accurate model the risks because that is only seen as
| a function of small choices standing by themselves. A
| larger, overall approach is what is very often called for
| and it would help to have a tool in hand to both make
| that case and to give the counterparty the vocabulary and
| the required understanding of the subject in order to
| have a meaningful conversation.
|
| Edit: please post your link from above as a separate
| submission.
| smcin wrote:
| Your writing is good, please keep at it. I think it would
| help a lot if you made it clearer when you're talking
| between root-cause-analysis for software, aviation, other
| things, or generically.
|
| Also, your train-of-thought is pretty deep; bulleting
| runs out of steam and gets visually confusing, especially
| with the article table-of-contents on RHS, you're only
| using <50% of screen width. Suggest you need
| numbered/lettered lists and section headings and use the
| full screen width.
| ratorx wrote:
| Google's SRE STPA starts with a similar model. I haven't
| read the external document, but my team went through this
| process internally and we considered the hazardous states
| and environmental triggers.
|
| https://sre.google/stpa/teaching
|
| Disclaimer: currently employed by Google, this message is
| not sponsored.
| AnthonyMouse wrote:
| > Trying to prevent accidents while not paying attention to
| hazardous states amounts to relying on the environment
| always being on our side, and is bound to fail eventually.
|
| The reason they had less than 30 minutes of fuel was
| _because_ the environment wasn 't on their side. They
| started out with a normal amount of reserve and then things
| went quite badly and the reserve was sufficient but only
| just.
|
| The question then is, how much of an outlier was this? Was
| this a perfect storm that only happens once in a century
| and the thing worse than this that would actually have
| exhausted the reserve only happens once in ten centuries?
| Or are planes doing this every Tuesday which would imply
| that something is very wrong?
| kqr wrote:
| This is why staying out of hazardous conditions is a
| dynamic control problem, rather than a simple equation or
| plan you can set up ahead of time.
|
| There are multiple controllers interacting with the
| system (the FADEC computer in the engines, the flight
| management computer in the plane, pilots, ground crew,
| dispatchers, air traffic controllers, the people at EASA
| drafting regulations, etc.), trying to keep it outside of
| hazardous conditions. They do so by observing the state
| the system and the environment is in ("feedback"),
| running simulations of how it will evolve in the future
| ("mental models"), and making adjustments to the system
| ("control inputs") to keep it outside of hazardous
| conditions.
|
| Whenever the system enters a hazardous condition, there
| was something that made these controllers insufficient.
| Either someone had inadequate feedback, or inadequate
| mental models, or the control inputs were inoperational
| or insufficient. Or sometimes an entire controller that
| ought to have been there was missing!
|
| In this case it seems like the hazard could have been
| avoided any number of ways: ground the plane, add more
| fuel, divert sooner, be more conservative about weather
| on alternates, etc. Which control input is appropriate
| and how to ensure it is enacted in the future is up to
| the real investigators with access to all data necessary.
|
| -----
|
| You are correct that we will not ever be able to set up a
| system where all controllers are able to always keep it
| out of hazardous states perfectly. If that was a thing we
| would never have any accident ever - we would only have
| intentional losses that are calculated to be worth their
| revenue in additional efficiency.
|
| But by adopting the right framework for thinking about
| this ("how do active controllers dynamically keep the
| system out of hazards?") we can do a pretty good job of
| preventing most such problems. The good news is that
| predicting hazardous states is much easier than
| predicting accidents, so we can actually do a lot of this
| design up-front without first having an accident happen
| and then learning from it.
| thaumasiotes wrote:
| > This is why staying out of hazardous conditions is a
| dynamic control problem
|
| I don't think this philosophy can work.
|
| If you can't control whether the environment will push
| you from a hazardous state into a failure state, you also
| can't control whether the environment will push you from
| a nonhazardous state into a hazardous state.
|
| If staying out of hazardous conditions is a dynamic
| control problem requiring on-the-fly adjustment from
| local actors, exactly the same thing is true of staying
| out of failure states.
|
| The point of defining hazardous states is that they are a
| buffer between you and failure. Sometimes you actually
| need the buffer. If you didn't, the hazardous state
| wouldn't be hazardous.
|
| But the only possible outcome of treating entering a
| hazardous state as equivalent to entering a failure state
| is that you start panicking whenever an airplane touches
| down with less than a hundred thousand gallons of fuel.
| cyphar wrote:
| My understanding is that the SOP for low fuel is that you
| need to declare a fuel emergency (i.e., "Mayday Mayday
| Mayday Fuel") one you reach the point where you will land
| with only reserve fuel left. The point OP was making is
| that the entire system of fuel planning is designed so
| that you should never reach the Mayday stage as a result
| of something you can expect to happen eventually (such as
| really bad weather). If you land with reserve fuel, it is
| normally investigated like any other emergency.
|
| Flight plans require you to look at the weather reports
| of your destination before you take off and pick at least
| one or two alternates that will let you divert if the
| weather is marginal. The fuel you load includes several
| redundancies to deal with different unexpected
| conditions[1] as well as the need to divert if you cannot
| land.
|
| There have been a few historical cases of planes running
| out of fuel (and quite a few cases of planes landing with
| only reserve fuel), and usually the root cause was a
| pilot not making the decision to go to an alternate
| airport soon enough or not declaring an emergency
| immediately -- even with very dynamic weather conditions
| you should have enough fuel for a go-around, holding, and
| going to an alternate.
|
| [1]: https://www.casa.gov.au/guidelines-aircraft-fuel-
| requirement...
| janc_ wrote:
| Landing at an alternate location is significantly more
| expensive, so I assume Ryanair put pressure on its pilots
| to avoid that...?
| ndsipa_pomu wrote:
| That's very enlightening. I'm casually interested in
| traffic safety and road/junction designs from the
| perspective of a UK cyclist and there's a lot to be learnt
| from the safety culture/practices of the aviation industry.
| I typically think in terms of "safety margins" whilst
| cycling (e.g. if a driver pulls out of a side road in front
| of me, how quickly can I avoid them via swerving or brake
| to avoid a collision). I can imagine that hazardous states
| can be applied to a lot of the traffic behaviour at
| junctions.
| nabla9 wrote:
| >One pilot who reviewed the log said: "Just imagine that
| whenever you land with less than 2T (2,000kg) of fuel left
| you start paying close attention to the situation. Less than
| 1.5T you are sweating. But this is as close to a fatal
| accident as possible."
| ExoticPearTree wrote:
| > How much fuel should they have landed with?
|
| I think about 30 minutes worth of fuel.
|
| Not knowing their flight plan, it could have been that
| Edinburgh was the first alternate and Manchester the second
| alternate.
| kokekolo wrote:
| Similarly naive outsider, but I've read things here and
| there. My understanding is that they should have declared
| mayday (emergency) and landed (potentially at another
| airport, potentially in the middle of nowhere) _way_ before
| so that when they have landed they still had 30 minutes or
| more of fuel in the tanks.
| jakub_g wrote:
| How many go-arounds and alternates are usually accounted for?
| Assuming EU, high-airport density etc, typical 2h flight.
|
| Does the estimation change depending on weather forecast,
| season of the year etc?
| jacquesm wrote:
| 3 go arounds + 2 hours in a holding pattern should result in
| at least 45 to 60 minutes left in the tanks after landing.
| Depending on the kind of aircraft that can be a pretty
| impressive amount of fuel.
|
| > Does the estimation change depending on weather forecast,
| season of the year etc?
|
| Yes. There are many factors that go into this including trade
| winds (which vary quite a bit seasonally and which can make a
| huge difference), time of day, altitude of the various legs,
| route flown, weather, distance to alternates, altitude of the
| place of departure and altitude of the place where you are
| landing, weight of the aircraft, engine type, engine hours
| since last overhaul, weight of passengers, luggage and cargo,
| angle-of-attack and so on. The software I wrote was a couple
| of thousand lines just to output a single number and 10x as
| much code for tests, and it was just one module in a much
| larger pre-flight application.
| jakub_g wrote:
| I can only imagine how the test suite looks like. Wild.
|
| This made me think about the fuel itself: is aviation fuel
| globally standardised and the same quality in every single
| airport in the world?
| jacquesm wrote:
| The test suite was much larger than the code. It took
| ages to get it certified, the calculations had to be
| correct to the last significant digit on reference
| problems to prove that the algorithms had been
| implemented correctly. This caused a bit of a headache
| because the floating point library that I used turned out
| to be slightly different than the one from the benchmark.
|
| There are three different kinds of jet fuel and all are
| produced to strict standards, and then there are
| allowances for ppm water contamination (very low, to
| ensure the fuel system will never freeze at altitude or
| in freezing weather on the ground or at lower altitude).
| YeahThisIsMe wrote:
| I remember this stuff being a bigger story for a short moment x
| years ago, where low cost carriers (it might have been Ryanair
| then, too) routinely flew with unreasonably small amounts of
| "backup" fuel and had to declare emergencies in order to get on
| the ground safely.
|
| I guess they're trying it again now that the whole thing had
| blown over.
| cosmicgadget wrote:
| Pretty obviously not the case here if you read the article.
| coolThingsFirst wrote:
| const estimateFuel = (distanceInKms, litersPerKm) =>
| distanceInKms * litersPerKm;
| BenjiWiebe wrote:
| I don't even know what I'm talking about, but you at least
| forgot to account for headwinds and differing drag amounts at
| different altitudes/speeds.
| jacquesm wrote:
| The big one is the trade winds. Those can really kill your
| efficiency on long distance flights.
| coolThingsFirst wrote:
| Yes it was a bit of humor, sad it didn't land.
| fidotron wrote:
| I have known former air traffic controllers that won't fly
| certain airlines because of a notorious habit some have for
| queue jumping by claiming they're low on fuel. If they are low
| on fuel is something else, but in any case when the ATCs have
| noticed a pattern then something is up.
|
| This situation sounds a lot less nefarious, but it does also
| sound like they should have rerouted earlier.
| kpmcc wrote:
| Which airlines? I feel like if this is an issue we should be
| naming names.
| estebank wrote:
| RyanAir is famously one of them.
|
| Edit: I was recalling articles claiming the company
| purposely fueling less than other airlines in order to
| increase their rate of claims for priority landing to have
| a better "on time" statistics.
|
| This forum post disputes that:
| https://aviation.stackexchange.com/questions/38501/is-it-
| tru...
| PunchyHamster wrote:
| also carrying less fuel does save on fuel usage
| fidotron wrote:
| No way.
|
| Having attended meetings at ICAO I can also tell you many
| details of various aviation incidents, including their
| existence, are covered by some secret classification. This
| fact being disclosed caused most of the attendees to lose
| all hope in the rest of the proceedings. To their credit
| the FAA reps on that occasion were by far the most
| reasonable gov representatives in the room, and the FAA are
| one of the major voices pushing for greater transparency on
| it.
| nradov wrote:
| Which specific _civil_ aviation incidents are covered by
| some secret classification?
| SJC_Hacker wrote:
| > Which specific civil aviation incidents are covered by
| some secret classification?
|
| You would have to have secret clearance to know which
| ones
| nradov wrote:
| It's cool, I have Top Secret Level 3 (Omega Sector)
| clearance so you can go ahead and tell me.
| alwa wrote:
| It's generous of the classifying authority to send to the
| ICAO meeting somebody both appropriately credentialed to
| know about the information in question, and willing to
| talk coyly about it. Did these additional incidents
| inform the policy discussions at the meetings you
| attended?
| fidotron wrote:
| It's funny you say that, because the way it happened was
| it was blurted out by a diplomat from a certain country,
| at which point most of the regulators facepalmed and all
| of those of us from outside were having the same reaction
| as many here.
|
| The whole subject of discussion prior to this was efforts
| to improve data sharing wrt incidents.
| jacquesm wrote:
| Claiming you're low when you are not is going to cause a
| major headache for the PIC, they're going to have to write
| that up and they may well be investigated. If it turns out
| they were lying they would likely find out that that is a
| career limiting move and if it happens too often then that
| too should result in consequences. The main reason is that
| your fake emergency may cause someone else to have a real
| one.
| ashdksnndck wrote:
| What's the mechanism for them to get caught?
| jacquesm wrote:
| Random spot checks. Every day at every airport some of
| these will get verified. Also, the next pilot would have
| to be willing to cover for you because they are going to
| have to falsify their records to make your trick
| invisible. You record the amount of fuel in the tank when
| you take command of the aircraft, the amount of fuel that
| was loaded and from that it is trivial to compute how
| much was left the last time it landed.
| refulgentis wrote:
| Lets say a plane crew claims low fuel.
|
| The pilot in charge has to file a writeup.
|
| When someone accepts the writeup, there's a random chance
| it's selected for followup. If/when they discover there
| was enough fuel, it will affect the career(s) of
| person(s) involved.
|
| First, generally, people don't like having to do
| paperwork, and especially don't like doing paperwork to
| help you land a little quicker.
|
| While one time may not be a fireable offense, you will
| find you career affected in the number of ways people can
| find to be uncooperative with you, or not support you
| when you attempt to advance your career within the
| company.
|
| Developing a habit would lead your interlocutors to
| escalate the situation, which would lead to discipline up
| to and including the company firing person(s) involved.
| mlyle wrote:
| When you declare a fuel emergency or even urgency,
| there's often follow up to figure out why (mechanical
| issue? problem with dispatch? problem with flying
| technique? exceptional weather condition that could be
| forecast better? etc). And there is plenty of data in
| aviation to know what happened.
|
| Dispatch knows how much fuel they say they put in.
|
| Your flight time, speeds, and profile are known.
|
| ACARS may be reporting fuel use throughout the flight.
|
| etc, etc, etc.
| lenerdenator wrote:
| Kinda surprised there's no data link for that sort of
| telemetry so that you don't necessarily have to take the
| pilot's word for it.
| jjk7 wrote:
| Would that be more reliable than just ensuring there are
| consequences for lying?
| lenerdenator wrote:
| Perhaps. If the pilot knows that the ATC can see he's
| full of it, he might be less likely to lie.
|
| Those who still do can be grounded and be moved into
| management or take up a career in politics.
| jacquesm wrote:
| As a rule airline pilots don't lie about this stuff. They
| take safety pretty seriously.
| mrguyorama wrote:
| Putting a theory of "you shouldn't trust pilots" into ATC
| breaks the entire system.
|
| It is a system built out of very regulated parts, very
| professional people, and tight controls.
|
| Pilots are encouraged to be very forward and proactive
| about fuel situations because of
| https://en.wikipedia.org/wiki/Avianca_Flight_052
|
| Minimum fuel requirements are calculated as "Time of fuel
| for _cruise_ to certain points ", which is usually good
| enough, but if an Airport is stupid busy, or has bad wind
| patterns, just a couple go-arounds will chew through your
| fuel way faster than the regulation expects.
|
| Turbofan engines are also dramatically less efficient at
| low altitude than high altitude cruise. So holding at low
| altitudes because a congested airport is dealing with
| traffic will chew through your reserves much faster than
| you expect.
|
| Ryanair flies short hops to congested airports. They will
| have relatively low reserves, and you should expect them
| to run into "Hey we are low on fuel" more often than
| international flights for example.
| inglor_cz wrote:
| "It is a system built out of very regulated parts, very
| professional people, and tight controls."
|
| Locally, this is true. Globally, not so much. I remember
| my friend's vivid description of a flight taken in Nepal.
| It was absolutely wild.
| sgjohnson wrote:
| > It is a system built out of very regulated parts, very
| professional people, and tight controls.
|
| also worth mentioning that most of the civil aviation
| regulations and SOPs regarding commercial flights are
| written in blood.
| whycome wrote:
| I'm surprised the "fuel on board" isn't something
| communicated via transponder considering previous low
| fuel emergencies/crashes.
| sgjohnson wrote:
| It wouldn't change anything. The line between a "mayday -
| fuel emergency" and any other flight waiting for a
| landing slot is crystal clear. Of course, in low-but-not-
| emergency fuel scenarios the pilots can request priority,
| but the ATC don't have to oblige them.
| gus_massa wrote:
| I expect that they take the pilot's word in case of a rare
| situation [1] and then make the fill a ton of paparwork to
| try to solve the main cause and also discourage lies.
|
| [1] In one case someone mixed imperial and metric unix, and
| instead of $something-kilograms, they put only $something-
| pounds of fuel.
| kbolino wrote:
| This incident is known as the Gimli Glider and was
| actually due to multiple failures before the pound-
| kilogram issue (and the backdrop of Canada's then-recent
| metrication) even became relevant:
| https://en.wikipedia.org/wiki/Gimli_Glider
| MadnessASAP wrote:
| Second guessing a pilot saying they have a problem is a
| really bad idea. ATC second guessing an emergency is a
| _really_ bad idea. Making a pilot explain why they 're
| actually low on fuel, despite whatever some computer is
| saying, instead of focusing on flying the plane is a
| _really, really_ bad idea.
|
| Also, that sort of telemetry does exist for most major
| airlines, however it goes via satellite to the airline not
| the ATC.
| hermannj314 wrote:
| I am not saying you are wrong, but both Type I and Type
| II errors are problematic. What if the pilot is wrong?
|
| Korean Air Flight 801 could have used someone 2nd
| guessing a pilot. They didn't until they were almost dead
| and then it was too late. Not 2nd guessing the pilot was
| a really really bad idea.
| throwup238 wrote:
| If the pilot is wrong you hope the copilot or someone
| else on the crew picks up on the error and corrects it.
| If they're both wrong, or if they don't feel empowered to
| challenge the pilot like in Korean Air 801, everyone is
| usually fucked.
|
| ATC doesn't have the kind of situational awareness or
| manpower to fix these kinds of problems the vast majority
| of the time. It only seems like they could have done
| something after the fact when the disaster has already
| happened and hindsight activates.
|
| Like the GP said, ATC second guessing pilots is a
| _really, really_ bad idea. A few incidents doesn't change
| that.
| jacquesm wrote:
| That specific incident resulted in a lot of changes to
| the rulebook and some very specific notes about training
| in terms of cultural differences.
| PunchyHamster wrote:
| > Korean Air Flight 801 could have used someone 2nd
| guessing a pilot.
|
| ...yeah, the second pilot. And in this case, also flight
| engineer.
|
| IIRC The problem was pretty much aside from errors the
| cultural issues with pilots, the "lower ranks" wouldn't
| dare to be assertive to seniority and just voiced the
| issues they saw without doing anything.
| 7952 wrote:
| Might be useful for fire crews in an emergency. Maybe have
| data for souls on board also.
| nostrademons wrote:
| Since there's a lot of confusion in the comments below I'm
| going to hijack one of the top comments to make a couple
| points clear from the article and FlightRadar24 data: [1]
|
| They did reroute earlier. It was 2 failed attempts on
| Prestwick (Glasgow), 45 minutes in the landing pattern, then
| they diverted to Edinburgh (15 minute flight), a failed
| attempt at Edinburgh (~5-10 minutes), and then they diverted
| to Manchester (45 minute flight) and landed successfully
| there. Likely they hit their reserve just as the Edinburgh
| landing failed and decided to fly to Manchester, with clearer
| skies, rather than risk another failure in their reserve.
|
| IMHO the only questionable pilot decision here is to divert
| to Edinburgh rather than Manchester immediately. But this is
| somewhat understandable: first of all, dropping the
| passengers off at Edinburgh (an hour drive from Glasgow) is
| significantly less costly and less inconvenient than dropping
| them at Manchester (an overnight bus ride). Second, if the
| Edinburgh landing had been successful they would not have
| eaten into their reserve and no investigation would've been
| needed. Third, the Monday-morning quarterbacking could've
| easily gone the other direction if they had diverted to
| Manchester ("Why did you choose an airport 178 miles away and
| risk eating into your fuel reserve when Edinburgh was _right
| there_? ")
|
| [1]
| https://www.flightradar24.com/data/flights/fr3418#3c7f91f4
| dboreham wrote:
| Quick note that Preswick is not really Glasgow (35 miles
| away) and Glasgow has its own airport which presumably was
| also affected by the same weather so they couldn't divert
| to that. Between the Scottish lowlands (where they had
| already tried all the commercial airports) and anywhere
| else, Manchester is about the closest option.
| allturtles wrote:
| As someone totally ignorant of British airports, a Google
| maps search for "airports northern england" shows
| Teesside, Carlisle, and Newcastle all significantly
| closer to Edinburgh than Manchester. Are these not places
| where a 737 under emergency could land? Or was the
| weather also bad there?
| nicoburns wrote:
| > Or was the weather also bad there?
|
| That's likely, these places are not very far apart, and
| weather systems that cause 100mph winds don't tend to be
| small. And presumably if you have at most one landing
| attempt remaining you don't want to be taking any more
| chances.
| pmyteh wrote:
| Carlisle is small (and not currently licensed for public
| use) - not an ideal place to drop a 737 if there's a
| choice. It's also not that far from Prestwick so may have
| had similar weather. Newcastle and Teesside are both on
| the East coast and likely to be affected by similar
| weather to Edinburgh given the storm coming in from the
| North East. The next closest will be Manchester or
| Leeds/Bradford, with Manchester being larger, closer to
| where passengers want to go (Glasgow) and further away
| from the storm.
|
| There's precedent for this kind of situation to generate
| quite extensive investigations. An incident in 2017 where
| a flight from the Isle of Man to Belfast was unable to
| land in a storm, diverted back to the IOM, then landed in
| unsafe weather conditions because of insufficient fuel to
| divert again got a 48 page report[0], safety
| recommendations, and the airline being banned from the
| UK.
|
| [0]: https://assets.publishing.service.gov.uk/media/5a82e
| de440f0b...
| rjsw wrote:
| Leeds/Bradford is on a plateau and can get affected by
| wind.
| mr_toad wrote:
| Carlisle is a small domestic airport. The other two might
| have been affected by the storm as well. The weather was
| bad enough to down trees in London.
| hencq wrote:
| > IMHO the only questionable pilot decision here is to
| divert to Edinburgh rather than Manchester immediately. But
| this is somewhat understandable: first of all, dropping the
| passengers off at Edinburgh (an hour drive from Glasgow) is
| significantly less costly and less inconvenient than
| dropping them at Manchester (an overnight bus ride).
|
| Yeah, as someone who knows next to nothing about airlines,
| but has seen these type of decisions in businesses, this
| was the thing that stood out to me. This is all pure
| speculation of course, but I'd be curious how clear it was
| that Edinburgh would also have a high risk of being
| unsuccessful and whether the pilots felt any pressure to
| try that anyway. E.g. are there consequences for pilots who
| cause delays for passengers?
| PunchyHamster wrote:
| > E.g. are there consequences for pilots who cause delays
| for passengers?
|
| I'd imagine heavily depends on how often that happens vs
| other pilots on same route. Tho I'd imagine consequences
| are "here is more training".
| NetMageSCW wrote:
| To me the 45 minutes in the landing pattern also seems
| questionable.
| nostrademons wrote:
| At the point they left it, they still had about an hour
| and 20 minutes of fuel remaining, with an alternate
| airport 20 minutes away. They had not declared an
| emergency, so they were in with any other traffic waiting
| for takeoff and landing. (Which does make me wonder, did
| any other planes try to land at Prestwick at the time and
| how did they fair?)
| tonyhart7 wrote:
| so the pilot fucked up either way right????
|
| when you piece it together like that its a close call and
| maybe a hindsight but its understandable if pilot do this
| rlpb wrote:
| > IMHO the only questionable pilot decision here is to
| divert to Edinburgh rather than Manchester immediately.
|
| The decision will have been made based on the forecast
| weather at Edinburgh prior to the flight (that is used to
| select a suitable alternate), and the actual reported
| weather at the time. Both the forecast and actual weather
| are precisely reported in an aviation weather language
| ("TAF" and "METAR") and assessed objectively. The
| investigation will certainly consider if the pilots erred
| there. Mostly likely the outcome will be that the decision
| was the correct one given the weather information they had
| available to them - this is what has been found in similar
| previous incidents.
| inglor_cz wrote:
| "claiming they're low on fuel"
|
| It is almost fascinating how humans will stoop to dishonesty
| even in banal situations - and not just any humans, but
| pilots, who should be subject to at least some vetting.
|
| Maybe planes should be retrofitted as to transmit their
| actual fuel state including a qualified assessment in minutes
| to the ATC. Not just because of the cheaters, but also to
| warn the ATC in the rare case that some plane crew isn't very
| assertive about their dwindling fuel, or hasn't noticed the
| problem.
|
| It would make prioritizing the queue a bit more neutral.
|
| If I designed such a system from scratch, "remaining fuel"
| would be part of my telemetry.
| sebzim4500 wrote:
| >If I designed such a system from scratch, "remaining fuel"
| would be part of my telemetry.
|
| Careful what you wish for. I'd rather people skip the queue
| by pretending to be low on fuel than people skip the queue
| by actually being low on fuel.
| inglor_cz wrote:
| You mean that ATC would abuse their position by making
| planes circle as long as they have some fuel left?
| sebzim4500 wrote:
| No I mean people would take off with less fuel so that by
| the time they reach their destination they could skip the
| queue
| inglor_cz wrote:
| This is provable, though (there are regulations that say
| how much fuel you must have at takeoff - enough to divert
| comfortably to a suitable airport + some reserve for
| circling), and could be heavily punished. Up to the
| withdrawal of necessary licences.
| geor9e wrote:
| Do forecasted storms go into the fuel estimate formulas?
| jacquesm wrote:
| Yes. Even not forecasted storms in the form of a probability
| of wind at low altitude when the engines are at their least
| efficient. And tradewinds at altitude, which are quite
| variable as well.
| huijzer wrote:
| > I'd be very wary to get ahead of the investigation and make
| speculative statements on how this could have happened, the one
| thing that I know for sure is that it shouldn't have happened,
| no matter what.
|
| Just watch Juan Browne, he usually turns out pretty good in
| analyzing the mishaps. He didn't upload anything for Manchester
| yet but will probably soon: https://youtube.com/@blancolirio
| loeg wrote:
| I'm also a Blancolirio subscriber. Juan also doesn't try to
| get ahead of the investigation, really. It's part of what
| makes him a valuable voice in the space.
| bartread wrote:
| Yeah, again, I'm going to wait for the Mentour Pilot analysis
| on this one.
| j45 wrote:
| Very insightful, thanks. Glad everything was ok.
|
| All I had to contribute was to ask if they were trying to
| hypermile or something?
| davesque wrote:
| Yeah, to give some idea, I believe the technical term that
| would have been radioed from the pilot in this situation would
| have been "mayday fuel."
| ecommerceguy wrote:
| I'm just curious, is this hard on the fuel pumps? I've always
| been told to not run gas down in your car because the pumps
| will get hot.
| t0mas88 wrote:
| The pumps are fuel cooled, but it's designed such that the
| pumps remain in the fuel even in a low fuel situation.
| ChrisMarshallNY wrote:
| _> it shouldn 't have happened, no matter what_
|
| You hear that a lot, with Ryanair stories.
|
| Sounds like a great airline!
| patrickmcnamara wrote:
| Ryanair has an impeccable safety record.
| XorNot wrote:
| This honestly makes me think that we're missing a trick if an
| option for this sort of circumstance can't be "send a military
| fuel tanker up to refuel them in air" as a last ditch emergency
| measure (which IMO you would've triggered in this exact
| scenario).
|
| The argument in favor is simply that we need in air refueling
| for the military, but justifying all that expenditure is a lot
| easier if it's dual use technology.
| darthwalsh wrote:
| Isn't midair refueling notoriously difficult to get right?
| The headlines would become "airliner crashes after crew
| couldn't thread the needle for 45 min"
| TZubiri wrote:
| >I'd be very wary to get ahead of the investigation and make
| speculative statements on how this could have happened
|
| >Ryanair
|
| I wouldn't be so wary.
| bboygravity wrote:
| "make speculative statements"
|
| isn't this 99 percent of modern infotainment "journalism"
| though? making speculative statements, omitting and lying..
| PaulRobinson wrote:
| The context you're missing is that Ryanair have routinely
| declared fuel emergencies in the past, and it seems an
| operational tactic - they want to carry less fuel to burn less
| fuel, and then have to regularly mayday to jump the stack on
| inbound, saving cash. That's not covered in the article, but
| you can sure as hell expect the CAA are going to take another
| look at them and their operations planning.
|
| On this one, they did 3 attempted landings at Prestwick. [Edit:
| I now see that the third attempt was at EDI] What happened
| between the first and the second landing that made them think
| on their second go-around that a third attempt was more likely
| to succeed than the previous two? Was the wind dying down, or
| was the captain just feeling a bit braver or stupider? [Edit:
| I'm still curious as to what information they gathered that
| landing conditions were significantly different at EDI to make
| that diversion, given its relatively close and so likely to
| have similar weather].
|
| Why was their final reserve Manchester when there were
| literally dozens of closer suitable airports, at least some of
| which are likely to have had better wind conditions by virtue
| of lower gusts, or more aligned to runway direction so not
| dealing with a strong crosswind?
|
| There are many reasons I won't fly Ryanair, but not least
| because they have been shown over and over again to make
| reckless planning and operational decisions, and they are
| fortunate to have not had hull losses as a result. Time is
| ticking down, variance will catch them one day, and a sad &
| tragic catastrophe is only a matter of time. People will go to
| prison as a result, because this pattern of behaviour shows
| that this isn't "bad luck", it's calculated risk taking with
| passenger and crew lives to save money.
| normie3000 wrote:
| > There are many reasons I won't fly Ryanair
|
| I swore off them a decade ago when I realised how adversarial
| their relationship with their passengers is.
|
| Until an accident does happen, I have no doubt they'll
| trouser a lot of cash.
| gizajob wrote:
| I fly with them all the time and never have any kind of
| issue at all. They offer a good deal, ok there's a couple
| of obvious dark patterns in their app and way of doing
| business but they're hardly unique in that respect. Feels
| like getting a fast bus between European cities nowadays.
| anton001 wrote:
| But these bus companies have also been involved in fatal
| accidents more than a few times over the past years.
|
| Multiple as a result of driver error or no outside
| involvement from a third party.
| janc_ wrote:
| Not just adversarial to passengers but to their employees
| also.
| crmd wrote:
| I once had a board member who was also on the board of Ryan
| Air, and he casually told me a story about when their CEO
| gave a presentation on adding a credit card -powered
| interlock on the cabin lavatories. He told them, "They're my
| planes and if you have the nerve to shit in them you should
| have to pay for the cleanup".
|
| My colleague thought he was portraying the CEO as a cool guy
| and decisive manager, but I thought the guy sounds like a
| sociopath.
| mindslight wrote:
| Sounds like pilot error - they didn't pay the extra fee to have
| reserve fuel.
| addandsubtract wrote:
| "Worth it" - Ryanair probably
| deadbabe wrote:
| On the positive side, if they had made a crash landing with so
| little fuel, there would not likely have been a fiery explosion,
| and many more passengers would have survived than normal?
| jacquesm wrote:
| Air + fuel explodes just fine. You _really_ don 't want to
| crash an airliner. At landing speed the number of people dead
| will still be > 0 and the remainder has a good chance of being
| injured seriously.
|
| For instance:
|
| https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_1951
|
| This happened at landing speed (the airport is only a few
| hundred meters from the crash site) and the plane was at the
| end of its flight from Turkey, it did not catch fire. Still, 9
| people perished and the remainder were all but one injured 11
| of them seriously.
| deadbabe wrote:
| Only 7% died, pretty good for a plane of that size with a
| rough landing.
| jacquesm wrote:
| Yes, even though that is a harsh conclusion to make and for
| the families involved of course it doesn't matter at all.
| But as these come this was bad but still not nearly as bad
| as it could have been. They were about to cross one of the
| busiest highways in NL, another 100 meters and it would
| have been an entirely different story. The field they
| landed in is in the Haarlemmermeerpolder, so clay and it
| had just been plowed.
| 12_throw_away wrote:
| Dunno about "only" ... 99.99998% of flights kill 0% of
| their passengers. Even if "just" one passenger dies in an
| incident, your flight is already in the 0.00002th
| percentile for safety, very bad!
| PunchyHamster wrote:
| that was equipment failure crew had to fight it, not
| something predictable like running out of fuel
| eCa wrote:
| > and many more passengers would have survived than normal?
|
| This[1] kind of crash landing is very rare (in that case there
| was no fire despite being immediately after take off, perhaps
| because of the cold). Normally an outcome like this is only
| reasonable to expect if you actually reach a runway despite
| being out of fuel. Like Gimli[2].
|
| [1]
| https://en.wikipedia.org/wiki/Scandinavian_Airlines_System_F...
|
| [2] https://en.wikipedia.org/wiki/Gimli_Glider
| cosmicgadget wrote:
| Well there'd probably be a fire but not a sustained fire which
| would improve survivability.
| tclancy wrote:
| Username checks out. I don't think the fire is your first
| concern in a plane crash.
| Molitor5901 wrote:
| Possibly related, but not definite, this apparently has happened
| before with Ryan Air.
|
| https://avherald.com/h?article=454af355
|
| https://www.independent.co.uk/travel/news-and-advice/exclusi...
|
| These were not definitive but it did raise concerns due to the
| budget nature of the airline.
| AceyMan wrote:
| Under FAA rules this was a screwup. [edit: see my own reply]
| (However, the rules are subtle, so they can be partially
| forgiven.) However, I'm not only a dispatcher but also a
| philosophy BA, so I've found a good way to explain it.
|
| Your reserve fuel (the "extra" fuel over what the actual flight
| burn) can of course be used (hello, that's what it's there for)
| but--and here's the rub--you can never _plan_ on using it.
|
| That is to say, in this case, when they missed their first or
| second approach, they CANNOT say, "We'll use our reserve fuel and
| make another go at it" because that would be _intentionally
| planning_ to burn your reserve.
|
| You may only dip into your reserve when you _have no other
| choice_. In this case, when the only fuel they had left was
| reserve, they are obligated by law to proceed to the alternate
| airport, which clearly they did not do [correction: they _did_ do
| the proper thing; see my 2nd reply below]. No bueno.
|
| [this is a slight simplification (minor details omitted for
| brevity) but the kernel of the issue is properly described]
| crazygringo wrote:
| > _That is to say, in this case, when they missed their first
| or second approach, they CANNOT say, "We'll use our reserve
| fuel and make another go at it" because that would be
| intentionally planning to burn your reserve._
|
| Is that what happened? That's not in the article, what's the
| source?
|
| And other comments here are saying the third attempt was in
| Edinburgh, so they _were_ already trying to land anywhere
| possible by the third attempt.
|
| At what point are you saying they chose to _plan_ on using
| reserves when they still had any option for landing without
| reserves?
| whycome wrote:
| OP didn't have the full picture. They've offered appropriate
| edits/updates
| AceyMan wrote:
| Update: OK, if *Edinburgh* was their alternate and they _missed
| there_ and were then forced to bugout for Manchester, that 's
| then an example of when reserve is OK to be burned. (The
| 'slight simplification' I omitted was unpacking how the
| _alternate fuel_ plays into the process, but here, that was a
| key part of the series of events.) That 's what I get for not
| reading TFA first :-/
| behringer wrote:
| Not really, you should have enough fuel to make it to
| multiple alternatives or make emergency landing somewhere
| else. You should _never_ burn that last 45 mins unless you
| want to make the news and file a lot of paperwork.
| mmaunder wrote:
| The regs are quite specific on if and when we need an
| alternate, which is weather dependent, and what your fuel
| requirements are. And we don't really have the idea of
| "multiple alternatives", but I guess it's implied by the
| additional reserve - what us Americans call a reserve or
| the Europeans call "final reserve". In case you're curious,
| we use the TAF (termimal area forecast) to determine if we
| need an alternate, and use a 1,2,3 rule which is 1 hour
| before and 1 hour after arrival time we need ceilings of at
| least 2000 ft and 3 statute miles of horizontal visibility.
| hshdhdhehd wrote:
| Er.. and maybe crash and kill yourself, all your passengers
| and crew and people on the ground.
| themafia wrote:
| If you're into your reserves you should declare an emergency
| immediately to get priority in air traffic sequencing and
| control.
|
| Pilots may be organizationally disincentivized when making this
| decision.
| mmaunder wrote:
| It's required when using your reserve under EASA to declare
| Mayday Fuel.
| yieldcrv wrote:
| in what way do FAA rules apply to operators doing a European to
| UK flight in an airline that doesn't operate in the US?
| mmaunder wrote:
| Similar philosophies but with differences. e.g. FAA reserve
| requirements is destination + alternate + 45 mins reserve.
| EASA is destination + alternate + final reserve which is 30
| mins holding for jets and 45 mins for pistons IIRC. But in
| both cases it's that idea of a destination, an alternatite,
| and additional. And then there's the requirements around
| whether you need an alternate, etc.
| averageRoyalty wrote:
| I was wondering that too. I've taken it to mean "if this
| situation had happened in the Americas..." as the most
| generous interpretation I can make.
| AceyMan wrote:
| See my comment, https://news.ycombinator.com/item?id=45541096
| [I am expert in CFR 14 Part 121, so I made reference to the
| regulations I'm qualified to directly speak on.]
| mmaunder wrote:
| "Under FAA rules this was a screwup."
|
| Not necessarily. And I get that you've caveated yourself with
| an edit and a reply etc, but lets assume that you're not
| hedging for the moment.
|
| They carried required reserves on departure. Multiple
| approaches thwarted by extreme unforseen weather. They declared
| Mayday Fuel, which is mandatory under EASA regulations, when
| reserve fuel use became unnavoidable. They diverted to the
| nearest suitable airport.
|
| Landing with 220kg is close, but within bounds of a declared
| fuel emergency.
|
| Crew decision to declare Mayday and divert was proper
| airmanship, not negligence.
|
| Yes, reserve fuel may not be planned for. But it may be used.
| It's there for a reason. Your accusation doesn't account for
| dynamic evolving weather and realtime decision making.
|
| I'm an instrument rated pilot and an advanced ground instructor
| under FAA and I fly IMC in bad weather as single pilot IFR
| around the pacific northwest and colorado.
| qazxcvbnmlp wrote:
| This is the right answer.
|
| Was this good/bad? Idk Room for improvement? Maybe? Clearer
| direction with the benefit of hindsight? Maybe. but the
| majority of the sentiment in the responses is coming from
| people not type rated in a 737.
| bsimpson wrote:
| Where's Nathan Fielder when you need him?
| rjh29 wrote:
| Some commenters are claiming the flight should have never
| taken off and that the weather situation was entirely
| predictable. What's your take on that?
| octo888 wrote:
| > Under FAA rules this was a screwup
|
| An oversight I'm sure they can fix ;-)
|
| FAA as a yardstick? Hm
| dclowd9901 wrote:
| > you can never plan on using it
|
| In off-roading, we have a similar rule with 4 wheel drive. You
| don't use it to go in, you use it to get out.
| robthebrew wrote:
| I imagine the next step will be RyanAir asking passengers to
| carry fuel cans onto the plane. B*tards.
| nomilk wrote:
| > One pilot who reviewed the log said: "Just imagine that
| whenever you land with less than 2T (2,000kg) of fuel left you
| start paying close attention to the situation. Less than 1.5T you
| are sweating. But (220kg) is as close to a fatal accident as
| possible."
| DamnInteresting wrote:
| Now _that_ is range anxiety.
| blizkreeg wrote:
| As a naive person, I have a simple question - why would they even
| fly to an airport where there's 100mph winds? Wouldn't ATC know
| this and tell the flight way in advance to fly to a different
| destination?
| NoiseBert69 wrote:
| Forecasts are based on multiple weather simulation runs.
|
| It's a often good working gamble that you will pick a short
| period of weather that is within your operational limits.
|
| Commercial pilots don't have "personal limits". It's defined by
| their airplane and/or companies constraints.
| martinald wrote:
| Because the weather is very changeable. You may get a lull in
| the wind for a couple of mins, enough to land.
|
| I've been on a couple of flights like that. Once where we did
| two attempts and landed on the 2nd, the other where we did 3
| but the had to divert. Other planes were just managing to land
| in the winds before and after our attempts.
|
| The other problem is (as I found out on that flight) that mass
| diversions are not good. The airport I diverted to in the UK
| had dozens of unexpected arrivals, late at night. There wasn't
| the ground staff to manage this so it took forever to get
| people off. It then was too full to accept any more landings,
| so further flights had to get diverted further and further
| away.
|
| So, if you did a blanket must divert you'd end up with all the
| diversion airports full (even to flights that could have landed
| at their original airport) and a much more dangerous situation
| as your diversions are now in different countries.
| w10-1 wrote:
| Can anyone say whether airline pilots make each diversion
| decision solely based on their own information and judgment, or
| do they loop in the company?
| AceyMan wrote:
| Unless they are in an emergency and are busy with aviating,
| they will coordinate with their dispatcher on diverting, even
| if only to verify that the weather at the intended alternate is
| still favorable. Per the FAA regulations, the PIC and the
| dispatcher have joint operational control over the flight. Of
| course, at the end of the day, only the pilots have their hands
| on the controls, so they can make the plane do what they want--
| but from a legal standpoint, the dispatcher and pilot-in-
| command have equal & shared responsibility for the safe
| operation of the flight.
| AceyMan wrote:
| I realize this is a UK carrier and was operating in the
| EU/UK, but for the most part, the rest of the world uses the
| US legal framework for aviation as a boilerplate for their
| own civil code. Yes, there are some differences, but these
| are usually minor and more of "differences in quantity"
| rather than "differences in kind". [Since the airplane was
| invented here the US had a head start on regulating civil
| aviation.]
| 12_throw_away wrote:
| Sure, company dispatchers are usually part of the conversation,
| and in non-emergency diversions (i.e. the vast majority), they
| may suggest specific airports that would be more convenient for
| company logistics. But the final decision is always the pilots'
| - and once they've declared an emergency, more or less every
| single airfield, including military, becomes available to them.
| inoffensivename wrote:
| Airline captain here.
|
| We definitely involve the dispatcher in the diversion decision.
| Especially if it's an unplanned diversion, where the big-
| picture view the dispatcher has is very useful for us in our
| metal tube.
| chrisshroba wrote:
| For anyone interested, here is the flight playback:
|
| https://fr24.com/data/flights/fr3418#3c7f91f4
| greggsy wrote:
| Sub required.
|
| I can wait for the Pete the Irish Pilot's take though.
| gregsadetsky wrote:
| this one is available - https://www.flightaware.com/live/flig
| ht/RYR3418/history/2025...
| nomilk wrote:
| Is there a way to hear the pilots / ground conversing?
| rawling wrote:
| I think monitoring ATC comms is banned in the UK.
| henryaj wrote:
| Certainly banned enough that you can't listen to ATC
| playback anywhere online. I think in practice you can use
| an air band radio at home (not sure how anyone would know
| if you were anyway).
| kristofferR wrote:
| This very recent Mentour documentary is extremely relevant, came
| to mind immediately. Multiple redirects due to bad weather,
| extreme "Get-there-itis" and eventually running out of fuel.
|
| Great edutainment if you're feeling in the mood for that. If
| you're inpatient you can skip to 14 minutes, before that it's
| just backstory.
|
| https://www.youtube.com/watch?v=vK_7q9tixX4
| rappatic wrote:
| > the Boeing 737-800 had just 220kg of fuel left in its tanks...
| enough for just five or six minutes of flying
|
| Maybe I'm just unaware, but it's crazy to me that these planes
| burn 40 kilograms of jet fuel _per minute._
| dcchambers wrote:
| Especially crazy considering the 737 is not a particularly
| large commercial aircraft.
|
| 40kg/minute is around 12 gallons (47 liters) of fuel per
| minute. Meanwhile a 777 burns around 42 gallons (160 liters)
| per minute. A 747 burns 63 gallons (240 liters) per minute -
| more than a gallon per second!
| warmwaffles wrote:
| Is that at cruising altitude?
| nicoburns wrote:
| That is why some people avoid flying for environmental reasons.
| Planes use crazy amounts of fuel.
| phyzome wrote:
| Yeah, when people say "flying has a high carbon footprint",
| they're _not kidding_. It 's really quite massive.
|
| I don't fly any more.
| Schiendelman wrote:
| Want to bake your noodle?
|
| Because the market responds to your behavior by slightly
| lowering the cost of flying to fill those seats, demand
| increases to match from slightly lower income people. Because
| they then organize their lives slightly more around cheap
| flights, it gets even harder to lower the impact of flying.
|
| Paradoxically, rich people like us (you're a tech worker
| too...) flying more, because we're less sensitive to price,
| leave more room for pricing in carbon reduction strategies in
| the tickets/taxes. If you have more seats from the lower end
| of the market... you don't have as much flexibility in
| solutions.
| dredmorbius wrote:
| Which is a strong argument for a carbon tax on (fossil)
| fuels. Indexed to consumption over greenhouse gas emissions
| targets.
|
| Taxes are one way to make markets internalise
| externalities.
| Schiendelman wrote:
| Hi, I'm the choir you're preaching to
| dredmorbius wrote:
| Sing louder, damnit!!!
|
| ;-)
| hshdhdhehd wrote:
| > leave more room for pricing in carbon reduction
| strategies in the tickets/taxes
|
| that is politically driven and has nothing to do with
| whether rich or poor bums are on seats.
| grapesodaaaaa wrote:
| Clearly you have thought a lot about carbon reduction, so I
| have a question for you.
|
| Is a plug in hybrid or EV less polluting if you don't have
| rooftop solar?
|
| edit: I think I know the general answer, but I'm splitting
| hairs comparing a replacement car for an ICE vehicle that I
| have.
| trapexit wrote:
| You don't need your own rooftop solar. You can time your
| charges for when power is cheap (i.e. renewables are
| highly represented in the grid mix). In many locations
| you can get an electricity tariff that changes by time of
| day, either fixed times of day or nearly real-time to
| track the current wholesale price.
|
| Here in Scotland, we have an EV electricity tariff that
| give us low rates between 00:30 - 05:30 while the wind
| turbines spin and demand is low, and our plug-in hybrid
| is programmed to charge during those hours. (We also run
| the dishwasher, washing machine, and tumble dryer on time
| delay during those hours as much as possible)
|
| With nearly all of our car trips being local, the ~25
| mile electric range the plug-in hybrid is rarely
| exceeded. We fill the petrol tank maybe once every 3 or 4
| months, or when we're on a road trip.
|
| Pure EVs are harder to justify in the UK currently unless
| you do basically all of your charging at home, because
| with 20% VAT added to the price of electricity from
| public chargers, and too-low fuel taxes, the per-mile
| cost is similar to--or sometimes more expensive than--
| driving on petrol. It's shockingly bad public policy.
| rjh29 wrote:
| Octopus Energy in the UK. Sometimes you can get paid to
| take power off the grid. Unfortunately batteries are too
| expensive to make really good use of it.
| FinnKuhn wrote:
| Don't look up the carbon footprint of driving then. That is
| even higher in comparison to most passenger flights.
| dewey wrote:
| The data on https://ourworldindata.org/travel-carbon-
| footprint disagrees, do you have a source?
| FinnKuhn wrote:
| It doesn't though. The vast majority of flights are
| short-haul or long-haul flights and not domestic. This
| data uses the UK flight data so let's look that up.
|
| Non-Domestic flight passengers: 14,124,617 [1] Domestic
| flight passengers: 1,455,330 [2]
|
| So you can see that over 90% of all passengers do not fly
| domestically within the UK. So only the domestic flights
| emit more CO2 than combustion engine cars, but they are
| the minority. If you were to look at the US, flights that
| short probably play even less of a role due to longer
| distances between cities in the US (in comparison to the
| UK).
|
| In conclusion the data you provided very much proves my
| point so thank you for providing the source for my
| statement yourself.
|
| [1] https://www.caa.co.uk/Documents/Download/10276/b2eeda
| db-6813... [2] https://www.caa.co.uk/Documents/Download/1
| 0276/b2eedadb-6813...
| Aeolun wrote:
| I don't think that's so much? A car burns 1 liter to travel 15
| kilometer'ish, and carries 4 people.
|
| An airplane burns 40 liters to travel 15 kilometers too (900
| kph), but carries 160 people.
|
| That's about 40x more than the car, so the fuel economy per
| passenger is about the same.
|
| Of course jet fuel is probably a bit more polluting, but it's
| still interesting how close it is.
| ant6n wrote:
| The greenhouse effects of flying is about 3-5x the effect of
| just burning the fuel.
| amadeusw wrote:
| What do you mean by this? What else than burning the fuel
| contributes to the greenhouse effect?
| Aeolun wrote:
| Building the airplanes? Servicing them? Heating the
| airports?
| DiscourseFan wrote:
| That's nebulous, are we going to claim that for all
| industrial processes?
| mierz00 wrote:
| Could you explain why this is?
| mercutio2 wrote:
| Water vapor in the stratosphere has a very high radiative
| forcing. Offset somewhat by particulates in the upper
| atmosphere.
|
| Cirrus clouds and contrails have a distinct, and large,
| additional forcing.
| mulmen wrote:
| 40kg of fuel per minute is a lot but airplanes carry a lot of
| people.
|
| Web searches suggest a 737-800 gets about 0.5mpg at cruise.
| With 189 passengers in a one-class layout that's 95mpg per
| passenger. With 162 in a two-class layout that's 81mpg per
| passenger.
|
| This is better than a single person in a car but four people in
| a Prius gets 50mpg * 4 = 200 mpg.
| AtlasBarfed wrote:
| This is what vexes me about the lack of emphasis on highway
| self-driving. Everyone's obsessed with robo taxis.
|
| An overnight trip that's automated could go at 40 mph and get
| seriously good gas mileage. I mean man with four people would
| probably get almost 100 miles per gallon.
|
| And this would eliminate a lot of short-range flights
|
| It should be a lot easier to implement than having to worry
| about a whole class of problems that robo taxis in cities
| have
| mulmen wrote:
| Sounds like a train.
|
| The robo taxi links the last few miles to transit.
|
| I recently travelled from my house in Seattle to my office
| in SF without ever getting in a car. I walked more in the
| airport than I did anywhere else.
|
| Home -> Walk 11 min -> Metro Bus -> light rail -> SEA -> SF
| -> BART -> Walk 2 min to Hotel.
|
| Next time I go down I'm going to take Amtrak. I couldn't
| this time because it was full. In 2024 360,000 people rode
| that route on 730 trips for an average of about 500 people
| per trip. Looks like Amtrak gets between 0.6 and 2mpg.
| That's 300mpg to 1000mpg per person which is better than a
| Prius' 200mpg at 40mph.
|
| Seattle to SF is 1019 miles. At 40mph that's 25 hours,
| which is an hour slower than the Amtrak schedule.
| hshdhdhehd wrote:
| Yes. Electric self driving cars are why I am not too
| concerned about all the tunnel and highway building. They
| are train tracks of the future.
| mulmen wrote:
| Train tracks are the train tracks of the future.
|
| Trains are far more efficient than cars, especially at
| scale.
| hshdhdhehd wrote:
| Assumes everyone is in medium to high density urban
| areas.
|
| I like the idea, rural life excepted, but hard to imagine
| sprawl will ever be replaced.
| mulmen wrote:
| It doesn't. Trains cover the same distances as airplanes.
| Take a train across Washington, or anywhere, most of the
| stops are small towns.
|
| Light rail, busses, and robotaxis cover sprawl.
| dredmorbius wrote:
| In commercial aviation (passenger/cargo), typically about
| _half_ the take-off weight is _fuel_. That 's not half the
| _payload_ weight (pax + cargo + fuel), it 's half the _takeoff_
| weight.
|
| For a medium-range flight (say ~2000 mi / 3200 km) each
| passenger incurs somewhat more than their own weight in fuel.
| mr_toad wrote:
| Each of the four F1 engines on the Saturn V burned 1.8 metric
| tonnes of liquid oxygen and 0.8 tonnes of rocket fuel _every
| second_.
| hydrogen7800 wrote:
| And each engine's propellant pumps required 55,000 HP to
| deliver that propellant.
| askvictor wrote:
| > 40 kilograms of jet fuel per minute.
|
| That is going to vary considerably between cruising and
| ascending.
| burnt-resistor wrote:
| Look at it (2.5 t/h) by volume (0.82 kg/L): 3 kL/h (790 gal/h)
| == 50 L/m (13 gal/m) == 830 mL/s (0.9 qt/s), and then divide
| the total flow rate by 2 for rate per engine.
|
| Or divide the total by the number of passengers (~189) flying
| to consider effective fuel economy (per passenger) or 13
| kg/pax/h or 3.6 g/pax/s.
|
| They must plan to never land with less than 30 minutes of fuel,
| or about 1.25 t, and I'd say they should never, ever land with
| less than 15 minutes in their career during a pan/mayday bingo
| fuel emergency.
| throwaway-0001 wrote:
| Better links
|
| https://avherald.com/h?article=52dfe5d7&opt=0
|
| https://www.reddit.com/r/aviation/comments/1nzet3a/flight_a_...
|
| Quoted:
|
| Incident: Malta Air B738 at Prestwick, Edinburgh and Manchester
| on Oct 3rd 2025, landed below minimum fuel By Simon Hradecky,
| created Sunday, Oct 5th 2025 14:39Z, last updated Friday, Oct
| 10th 2025 15:02Z
|
| A Malta Air Boeing 737-800 on behalf of Ryanair, registration
| 9H-QBD performing flight FR-3418 from Pisa (Italy) to
| Prestwick,SC (UK), was on final approach to Prestwick's runway 20
| when the crew went around due to weather. The aircraft entered a
| hold, then attempted a second approach to runway 20 about 30
| minutes after the go around, but again needed to go around. The
| aircraft again entered a hold, about 10 minutes after entering
| the hold the crew decided to divert to Edinburgh,SC (UK) where
| the aircraft joined the final approach to runway 24 about one
| hour after the first go around but again went around. The
| aircraft subsequently diverted to Manchester,EN (UK) where the
| aircraft landed on runway 23R about 110 minutes after the first
| go around.
|
| On Oct 5th 2025 The Aviation Herald received information that the
| aircraft landed below minimum fuel with just 220kg fuel (total,
| 100kg in left and 120 kg in right tank) remaining.
|
| The aircraft returned to service about 13 hours after landing.
|
| On Oct 10th 2025 the AAIB reported the occurrence was rated a
| serious incident and is being investigated.
|
| A passenger reported after the first go around at Prestwick the
| crew announced, they would do another attempt to land at
| Prestwick, then divert to Manchester. Following the second go
| around the crew however announced they were now diverting to
| Edinburgh, only after the failed approach to Edinburgh the crew
| diverted to Manchester.
| ro_bit wrote:
| > The Boeing 737-800 had just 220kg of fuel left in its tanks
| when it finally landed, according to a picture of what appears to
| be a handwritten technical log. Pilots who examined the picture
| said this would be enough for just five or six minutes of flying.
|
| For reference, passenger airlines immediately declare emergency
| if their planned flight path would put them under 30 minutes of
| fuel (at least in the US). Landing with 5 minutes remaining of
| fuel is very atypical
| dlcarrier wrote:
| The latest Captains Speaking podcast has an discussion about one
| of the hosts being in a similar situation:
| https://youtu.be/5ovlZ221tDQ
|
| Fortunately, the flight left with extra fuel, because it was
| cheaper to carry excess from the origin airport than to buy it at
| the destination airport, so reserve fuel wasn't needed, but it
| was close. Also, there was lots of lightning.
| prism56 wrote:
| I absolutely love insights like this into areas of the world I
| have no knowledge. Makes absolute sense in the modern world but
| also something I'd not think about
| themafia wrote:
| Trucking companies started adding this to their logistics
| about a decade ago as well. Once they had accurate fuel price
| information for most of the country they started telling
| their drivers precisely how much fuel to onboard at each
| stop.
| prism56 wrote:
| Yeah makes sense. Similar to my electric car now I think
| about it. Optimises charges based on capacity and price.
| schainks wrote:
| So this is about the stopping problem, but for airplane fuel,
| kinda?
| m3kw9 wrote:
| Another metric conversion error?
| stockresearcher wrote:
| The only real question for the inquiry is how the decision was
| made to divert to Edinburgh and whether that was a reasonable
| decision at the time.
| oncallthrow wrote:
| I look forward to watching this one on Mentour Pilot
| precommunicator wrote:
| Given it's Ryanair I doubt we will see it, still hope so (Peter
| works for them)
| dom96 wrote:
| I believe he's retired
| mnw21cam wrote:
| You'll probably have to wait a while. Petter is pretty
| insistent on waiting for the full incident report so that he
| can be completely thorough and avoid speculating.
| honkostani wrote:
| And that is how fuel reservoir requirements rise for all. Im
| sure, the whole airline industry is looking at the whole markets
| share prices going down- writing happy songs and packing gift
| baskets for Ryanair.
| ratelimitsteve wrote:
| The headline is about the landing, but the issue here happened at
| takeoff. There were 100 mph winds at the destination and this was
| their 4th fallback attempt and their third airport. This flight
| should never have taken off, the risk of multiple diversions was
| easily predictable, but the flight took off headed toward an
| airport in dangerous conditions, got diverted to a second airport
| that was just as dangerous, then finally to a third where
| conditions were so bad other flights were being cancelled
| (https://uk.news.yahoo.com/storm-amy-brings-flight-chaos-2019...)
| and where it finally landed because it was either land at that
| airport or land somewhere that is not at all an airport. Once
| this flight was in the air, disaster was more or less inevitable
| and we lucked into a narrow eviting window.
| moltar wrote:
| Is it like in the car where you have no fuel left but there's a
| reserve of another 10 liters?
| RajT88 wrote:
| Yes and no. I had this happen recently and looked into it.
|
| My wife has been using my car, which is a Diesel Golf with a
| fuel capacity of 14.5 gallons. We set off driving one Saturday
| to visit my parents, and I noticed the fuel gauge was below
| empty already. By the time I got to the gas station, I put 14.3
| gallons of fuel into it. I calculated that that works out to be
| about a cup and a half of fuel.
|
| So once you hit empty on my car, you definitely have a ways you
| can drive still. I feel comfortable driving about 30+ miles,
| and it's never died on me. That puts it at no more than 1
| gallon of fuel left in the car based on my experience (not
| scientific I know, but I've owned 2 of these cars, with about
| 190k total driven miles). It's a lot less than 10 liters from E
| to Dead on the roadside.
| PunchyHamster wrote:
| probably depends between cars. on my old civic fuel light is
| ~5L/1.3 gallons
| aunty_helen wrote:
| You shouldn't tempt fate with a diesel, or any direction
| injection car for that matter. The high pressure pump will
| shred itself very quickly as the diesel is used for
| lubrication.
| RajT88 wrote:
| Best Practice.
| PunchyHamster wrote:
| It's more like
|
| * enough reserve to waste some in traffic. On top of that *
| enough reserve to find gas station. On top of that * enough
| reserve to drive to neighbouring city for gas station. On top
| of that * enough to cruise 30 minutes around that neighbouring
| city looking for other gas station in case the previous ones
| were closed. On top of that * enough station to run around
| parking lot looking for space to park
| paulbjensen wrote:
| It reminds me of a Transavia flight from Girona to Rotterdam that
| had to be diverted to Amsterdam back in 2015 (1 attempt at
| Rotterdam, decided to divert to Amsterdam, then 2 attempts in
| Amsterdam).
|
| It was a particularly stormy weekend and it turns out from the
| article that they had 992kg of fuel left:
|
| https://avherald.com/h?article=489d4c3f
|
| Massive respect for pilots and the job they do.
| dzhiurgis wrote:
| The Guardian can't be trusted with their sensationalist
| headlines.
|
| The flight couldn't land in 3 other airports and eventually
| declared emergency.
| nisten wrote:
| Looks like the emergency reserve management worked?
| baby wrote:
| Ryanair: Cutting cost at all cost
| bombcar wrote:
| Each passenger will be required to bring a 5 gallon can of JET
| A.
| octo888 wrote:
| Yup. They also popularised excessive baggage under the seat,
| and I routinely used to see obvious hazards that would impede
| an evacuation. Staff would turn a blind eye. Probably still do
|
| Further, with the baggage being there in easy reach under the
| seat, I reckon people would be more tempted to take it with
| them when evacuating.
|
| That they're are a safe airline seems to be incredible luck -
| they have all the components for it not to be.
| 9front wrote:
| United Airlines Flight 173 ran out of fuel while circling
| Portland International Airport trying to troubleshoot a landing
| gear. Six more minutes of fuel could have helped the airliner to
| land in the Columbia river by the airport or belly land on the
| runway. The captain chose to keep troubleshooting and crashed
| just 6 miles away from the airport.
|
| https://en.wikipedia.org/wiki/United_Airlines_Flight_173
| higgins wrote:
| Nothing beats a Jet2 holiday...
| ionwake wrote:
| Story time, from my past.
|
| Waiting on full flight in Europe, good airport, for take off.
| Pilot says over speaker : " We are delayed becuase FUEL guy got
| UPSET on tarmac and has QUIT. We know need someone ELSE to fill
| the plane with FUEL. " Said in a COMPLETELY nonchalant voice.
|
| Immediately I get concerned, try not to think what cause a FUEL
| TECH to QUIT regarding THIS PLANE and fuel issue. Just close my
| eyes, relax.
|
| 2 minutes later pilot comes on intercom again "For some WEIRD
| reason, someone wants to get off the plane. Now we have to wait
| for ground crew to find his suitcasebecause of rules. How
| annoying.."
|
| Plane waits for an hour on tarmac for BOTH passenger to get off
| and for FUEL to be finally "resolved".
|
| Arrive eventually at destination.
|
| Most of the trouble would have been avoided if the pilot had not
| sounded nonchalant about a "NON ISSUE about FUEL that a
| technician just QUIT OVER". I swear i even rememebr saying the
| statement with a hint of humour, like what on earth is the
| problem.
|
| This is a true story, and the fact this incompetence happened to
| me, well I wouldnt have believed it otherwise.
| PunchyHamster wrote:
| lacking fuel in plane that has not started flying isn't exactly
| something that should stress anyone and most definitely non
| issue
| ionwake wrote:
| You missed the point of the story, the issue was not lack of
| fuel, it was a crew member quitting because of a fuel issue,
| most likely a misunderstanding.
|
| Fuel misunderstandings have resulted in numerous serious
| incidents, try googling it bro
| lyu07282 wrote:
| I imagine everyone involved know that they are doing dangerous
| things, not taking a drop more fuel than is legally required
| for profit, knowing that none of that is going to change unless
| there is a major accident... They keep[1] landing these planes
| with X minutes of fuel left, but it doesn't do anything, until
| some plane falls from the sky with 0 minutes of fuel left then
| everyone knew all along and the rules are changed and nobody is
| held accountable.
|
| [1] https://www.bbc.com/news/world-europe-19267153
| hshdhdhehd wrote:
| Had a 1 maybe 1.5h holding pattern in Oslo once in Ryanair where
| they hoped they could land in extreme snow. Then diverted in the
| end (surprise!). Happened in 2009 though. Joked they were very
| desperate to land at Oslo because they cant afford to divert.
| jwsteigerwalt wrote:
| This seems to be a case where the error was that the 2nd
| diversion was to another commercial/passenger airport. The
| situation after it was determined Edinburgh was a no-go was dire
| and making it to an airport like Manchester was a luxury they did
| not have safe fuel for.
| system2 wrote:
| Even fighter jets have more fuel reserves when they land. This is
| insane.
| anshumankmr wrote:
| This happened in my country with I think a Vistara flight, where
| they had 5 minutes of fuel left.
|
| I myself went from Bangalore to Delhi a couple of weeks back, and
| the poor pilots told the air hostesses at least twice or thrice
| to prepare for landing but the plane did not land until much much
| later.
| burnt-resistor wrote:
| This one is pretty straightforward so it doesn't need an AAIB
| report. Failure of pilots to brief destination weather conditions
| and anticipate proper bingo fuel accordingly. Storms in the area
| == brief max go arounds, brief alternates, and carry extra fuel.
| They screwed up by taking unnecessary risks of too many go
| arounds and barely making an alternate because they didn't play
| it safe by carrying additional fuel. Take these bold pilots to
| the chief pilot's office for an uncomfortable conversation
| without tasty snacks.
| tzahifadida wrote:
| Guess which airline I won't be flying with next time...
| jdhzzz wrote:
| Why such a large surplus?
| pcl wrote:
| Are there any good online databases with fuel level details for
| individual commercial flights? I've been on a few flights that
| had to circle for a long time / had a number of go-round
| attempts, and I've never been able to find details after the fact
| about how close to the margins we were.
| octo888 wrote:
| I wonder if the pilots considered Newcastle (or Teeside)? The
| METARs showed favourable weather conditions at Newcastle and many
| planes landed there that day without issue I believe. Also far
| closer to Edinburgh than Manchester. I wonder if they thought
| that Manchester being further south, had a better chance of
| better weather?
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