µo«H¤H: jamewang (mass)    ¬ÝªO: Aero
¤é´Á: Wed Mar 22 10:14:54 2000
¼ÐÃD: Re: ¤Ó±d



==> jamewang (mass) ªº¤å³¹¤¤´£¨ì:
>tacan penetration:
>what:"tactical air nevigation"....it devided into 2 kind : tacan and hi-tacan (
>     tacan is used for "low altitude(about below 10000ft)" plane. and hi-tacan
>     is for "hi altitude(above10000ft)" jet ....) .
>when:when you are in the high altitude and you want to decend and landing in 
>     that airport....
>how:there are a lot of military textbook to introduce it ..
>    if you want to process the tacan ,
> firstable , you must have a tacan penetration chart , or you recite it in 
>      your mind ...   
> if you got it and you are now in the air and you want use tacan for landing
> this airport.....you have to calculate the EAT(estimate approach time)
> and the heading that to intercept the IAF(initial approach fix)
> and request to the air controller :
> ex:kangshiung approach , wc-110 position "tainan tacan 110 radius , 45 miles
>    heading 180 request tainan hi-tacan penetration , EAT 25 ( present time
>    plus the time you reach to the IAF including holding pattern.....)
>    if the controller admit your request , you can direct to the IAF and 
>    remember reduce your airspeed to 250kias below before 3 minites to the IAF
> if the controller refuse your request , you can ask for a holding point and 
> wait for his admit....
>   if the controller admit your request but change your EAT...you still direct
>   to the IAF and after you reach the IAF you can join the holding pattern to
>   hold .....(but you should know how to waste the rest time by the holding 
>   pattern first...)
>by the way , cause the different heading to the IAF , there are three way to 
>begin you penetration or join holding pattern.......
>  1.directly 
>  2.tear drop 
>  3.pallele 
>how to explain these three pattern need draw a picture and i don't know how
to draw on line.....sorry ......so i assume you guys have known these...

right, you may need calculate the heading to the IAF ..MOST pilot hope the 
line to IAF is a straight line to saving the fuel and the time...
how to make a straight line to the IAF ?
firstabe , you need to adjust the airport tacan frequency (this step should
finished when you make your mind to access this penetration cause you need 
to report your position and plan how to do this penetration ) . then you see
this airport tacan map and adjust the IAF's course on your gage....
and by your gage you should know the the heading to the IAF and know the
distance to the IAF .and figure the time to the iaf out......
how you know these on a gage...it need draw again...and i assume you goe it..
 




and then you got to access the penetration problems.....you should calculate
the vertical velocity between the iaf and the arc.......and adjust your power
setting , dive angle , and even you need to use the speedbrake to keep the 
you got the right penetration rate......
by the way , how to calculat the v.v.   there got a function:

                 v.v = (¤U­°¨¤«× * ¨C¤ÀÄÁ¯uªÅ³t)³,* 100
         
                ¤U­°¨¤«×=«e¶i¯@¼Æ /  ®ø¥¢°ª«×(¦Ê§`)
                            
                TAS = IAS + ( IAS * ALT / 1000 * 2 %)
maybe you think you only need to adjust the power setting and dive angle to v.v
but as you know , this penetration called TACAN mean tactical way to decend
and the v.v is generally  huge...so in most airport tacan penetration , you 
need to use the speedbrake...........
             
--
* Origin: ¤¤¤s¤j¾Ç-¬üÄR¤§®qBBS * From: 202.39.232.81 [¤w³q¹L»{ÃÒ]
.