Originally Posted by
aviatorhi
it doesn't make sense to be to be limited to using higher flap settings (15,25) only at light weights when they are most beneficial at higher weights... any help on why this might be?
Higher flap settings are NOT beneficial at higher wts since the added drag reduces climb gradient. As I recall, 727 takeoffs at the highest weights required no more than flaps 5. If you fly the 737-200 long enough, you will encounter "improved climb" takeoffs at heavy wts on long runways that require not only reduced flap settings but also increased V speeds to meet minimum engine-out climb gradients. The T. O. must be balanced between the runway available & the engine-out climb capability of the aircraft.