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.
Wrong. That's all well and good when you've got 12000 feet of pavement in front of you. However, when you're at MTOW with only 6000 feet of pavement you have no choice but to use 30* and be on the edge of both the takeoff and climb performance.
@A37575...
I am looking at the FPPM and it is quite enigmatic as compared to the FPPMs for later iterations of the airframe. It's mainly a question of why the higher weights are not allowed for the higher flap settings. I understand the degradation of climb performance with higher flap settings, at the same time I'm used to being able to tabulate the tables and let them say what they will say. The reason it's of particular curiosity to me is that there is no prohibition I can find in regards to using a high flap setting at a high weight apart from lack of performance data. In my experience if something of this nature is a significant enough issue Boeing will address it somewhere (FCTM, AOM, ATM, FPPM, etc.) with a simple statement of "Don't do it" (usually in "warning" text), yet that doesn't appear to be the case here.