Aaaargh! Not that old chestnut!
I'm interested if anybody thinks there are real dangers in turning downwind at low level in windy conditions. I'm familiar with the theory, an aeroplane flies in a parcel of air and it doesn't matter if that parcel of air happens to be moving over the ground, but I still think there are very real dangers.
I think probably the biggest factors are the pilots *perception* of increasing airspeed speed due to the increasing groundspeed leading to the temptation to pitch up or reduce power, and the *perception* of the aircraft slipping as it turns across the wind leading to the temptation to unbalance the aircraft with innapropriate rudder input.
If it is a climbing turn to downwind there will be a tendency to lose airspeed because of the increasing tailwind component due to wind gradient.
(I also have a pet theory developed after spending many airline standby hours standing in a field flying a radio controlled model glider, that a gust is sharper than a lull, therefore:
When flying into wind the relatively sharp gust results in a momentarily increased airspeed, but the gentler lull results in a smaller loss of airspeed.
When flying downwind the relatively gentle lull causes a small gain in airspeed, but the sharper gust causes a bigger loss of airspeed.
It certainly felt like this was the case with the model - and no I wasn't being fooled by the winds effect on the models groundspeed, I was thermal soaring and tended to trim the model for just over min sink speed and then let it look after itself in pitch as much as possible. I freely admit this could be complete bollox, I haven't been able to find any information to support my little theory, and even if it is true it may not be particularly relevant to full size aircraft. Any thoughts?)
I'm especially interested to hear the views of John Farley, or anyone else who has spent a lot of time at high alpha, near the ground, on windy days, and maybe glider pilots are more likely to have noticed these effects? Are there any accident reports or studies that have looked into the effects of turning downwind at low level in strong winds?
THAI TUN