Ojuka
I have flown arcs at 210 kts in small turboprops but the turn on to the Final Approach Track / Localiser really is a knife edge well over max AoB to make the turn in time, and is far too gung-ho.
I don't know what the official publications say in your part of the world but, here, they say that the 2NM lead for the turn off the DME arc will only work if your radius of turn is 2NM. Thus, if your speed produces a greater radius of turn, you need to start the turn sooner, to account for the radius. Of course, if you're going like a bat out of hell at the time, your turn radius could be so large as to take your aircraft out of the protection area.
Here's some figures, using Pans Ops calculations, to give you an idea of how it works out :-
Associated conditions :
Altitude : 4000 FT
Temp : ISA +15
AoB : 25 degrees
Wind : Assumed zero.
At 160 KIAS (174 KTAS) = 0.95 NM (rounded adversely)
At 180 KIAS (196 KTAS) = 1.21 NM (rounded adversely)
At 200 KIAS (218 KTAS) = 1.49 NM (rounded adversely)
At 220 KIAS (240 KTAS) = 1.80 NM (rounded adversely)
At 240 KIAS (261 KTAS) = 2.14 NM (rounded adversely)
Obviously some additional allowance might be wise, if you expect a tailwind during the turn, but the above figures should give you an idea of the base amount by which you need to lead the turn. As a matter of interest, the speed that comes closest to a 2NM turn radius in the above conditions is 232 KIAS (253 KTAS).
Thus, in zero wind conditions, a speed of about 230 KIAS is about the most that you can use with a sustained 25 degree AoB.
I'm with you,
keithl! If there's a "new" Pans Ops, then I haven't got it either!
