Originally Posted by pudoc
Secondly, the first segment. My manuals say it starts from the end of the TODR to gear up but I was always taught it's lift off (so basically the end of TORR) to gear up. Which is correct? Is there a difference?
It depends whether you are talking of the take-off path (25.111) or the take-off flight path (25.115). The take-off flight path starts at 35 ft at theend of the TODR (25.113(a) and (b)). The first segment of the take-off flight path is from that point until the point where the landing gear is fully retracted.
The take-off path starts at the beginning of the takeoff and may be determined either from continuous demonstrated take-offs or by synthesis from segments. If the segmental method is used, the first airborne segment extends from lift-off to the point where the landing gear is fully retracted.
P.S.
If the segmental method is used, the airborne part of the take-off is based on free-air data without ground effect. If the continuous demonstrated take-off is used, it is based on the demonstrated performance until the airplane is out of ground effect.