FlyingCesspit
30th Aug 2002, 07:49
As I'm a relatively inexperienced IMC Rating holder, when I'm intending to do an instrument approach, I practice it first on FS2000. This also has the benefit that I can afterwards visualise the join and patterns I have actually flown. What I am finding is that the instructions given in text books and on my course don't seem to give the best methods, and I'd appreciate any informed comment or references.
There are 2 areas I'm concerned about:
1) Teardrop (Sector 2) joins. All the advice is to apply single Wind Correction Angle on the teardrop leg. However, I find that applying double WCA works better: I would put this down to allowing for drift during the teardrop turn as well as the straight leg.
2) Outbound leg calculation. There is a variety of methods given for this:
(Thom) 3 x WCA to a max of 30 degrees, unless this gives a direction within 30 degrees of wind, in which case use 2 x WCA. Add 1 second per knot of headwind.
(IMC Class) 3 x WCA unless this gives a direction within 30 degrees of wind, in which case use 2.5 x WCA. If this results in a direction within 45 degrees of wind, use 2 x WCA. Add 1 second per knot of headwind.
(US Web sites) 2 x WCA
(One US web site) 3 x WCA (claims this is now the accepted standard)
(VATSIM - http://home.t-online.de/home/n.vorstaedt/SpecialTraining/holdings.html#Fly) 3 x WCA. For a C172, add 2 seconds per knot of headwind (the usual 1 second/knot figure applies to a/c flying at 200 kts)
According to FS2000, the 3 x WCA rule seems to work best, but I'm concerned that this is too simple and under some circumstances could give bad results (e.g. if WCA >30 degrees, although this is probably academic)
There are 2 areas I'm concerned about:
1) Teardrop (Sector 2) joins. All the advice is to apply single Wind Correction Angle on the teardrop leg. However, I find that applying double WCA works better: I would put this down to allowing for drift during the teardrop turn as well as the straight leg.
2) Outbound leg calculation. There is a variety of methods given for this:
(Thom) 3 x WCA to a max of 30 degrees, unless this gives a direction within 30 degrees of wind, in which case use 2 x WCA. Add 1 second per knot of headwind.
(IMC Class) 3 x WCA unless this gives a direction within 30 degrees of wind, in which case use 2.5 x WCA. If this results in a direction within 45 degrees of wind, use 2 x WCA. Add 1 second per knot of headwind.
(US Web sites) 2 x WCA
(One US web site) 3 x WCA (claims this is now the accepted standard)
(VATSIM - http://home.t-online.de/home/n.vorstaedt/SpecialTraining/holdings.html#Fly) 3 x WCA. For a C172, add 2 seconds per knot of headwind (the usual 1 second/knot figure applies to a/c flying at 200 kts)
According to FS2000, the 3 x WCA rule seems to work best, but I'm concerned that this is too simple and under some circumstances could give bad results (e.g. if WCA >30 degrees, although this is probably academic)