Originally Posted by gatbusdriver
Could someone please help me. I have been looking for the answer to this question for most of the day.
What are the four segments used for take off performance?
I believe segment one is from the start of the take off roll to screen height.
Segment 2 might be from screen height to accel height.
But the i'm stumped. Could someone please give me the correct answer.
Cheers
From FAR 25...
Originally Posted by Amdt 25-72
Sec. 25.111 Takeoff path.
(a) The takeoff path extends from a standing start to a point in the
takeoff at which the airplane is 1,500 feet above the takeoff surface, or at
which the transition from the takeoff to the en route configuration is
completed and a speed is reached at which compliance with Sec. 25.121(c) is
shown, whichever point is higher.
.....
(d) The takeoff path must be determined by a continuous demonstrated
takeoff or by synthesis from segments. If the takeoff path is determined by
the segmental method--
(1) The segments must be clearly defined and must be related to the
distinct changes in the configuration, power or thrust, and speed;
(2) The weight of the airplane, the configuration, and the power or thrust
must be constant throughout each segment and must correspond to the most
critical condition prevailing in the segment;
So, the answer is, as always...."it depends" - upon your type of aircraft, and upon the choices the OEM has made in reducing the data.
If one were to GUESS for a specific aircraft, one might expect segments as follows:
- Ground roll to liftoff
- lift off to 35ft (assumed gear up at 35ft)
- Gear up to flap transition
- clean, final segment
But depending on what configurations you have and what transitions are required, you could easily have extra segments. (Say if you have an intermediate flap position between takeoff and clean...)