Flap retraction

[tommoutrie]

Pitch. It changes when I make a mode selection.

If you choose to take the flaps up at 400 feet at V2+20 the aircraft is still compliant. It has to comply with the climb gradient and I think its clear from all the posts on here that everyone agrees that if you take the flap up at 400 feet it will still comply with the climb. Thats what most people think the normal take off is - flaps up at 400 feet with a speed check of V2+20 (for my plane, different on others). Everyone seems happy that its compliant from 400 feet - well lets check that.. is everyone happy? Or is anyone of the opinion that once clean, if you have an engine failure you should reduce speed to V2 and reselect the take off flap? I've had that one sent privately too..

The flaps neither know nor care how high the aircraft is. If the gradient clean from 400 feet is good enough it will be good enough from wherever you actually select the flaps up because it will be the same gradient because the speed is correct.

I'm really open to the flaws in this but its exactly whats in the Bombardier manual and various Cessna manuals and the Embraer manual. The problem is that they don't explicitly deal with the engine failure after flap retraction in the climb case. They only deal in detail with the engine failure at V1 case.

I've got no issue with using 400 feet as a platform below which there should not be a flap retraction but I think its important that pilots retract the flap for the correct reason. I also think that its important that people understand whats happening. Close inspection of the 737 manual discusses reduced acceleration altitudes in the case of hot and high performance precisely because the gradient and climbs achieved once clean are better than the flapped gradients and climbs.

I'll be completely honest here. I've received a couple of fairly unpleasant emails regarding my professionalism and its not the sort of thing I enjoy reading so its time for me to call a halt to this. I'm sorry I brought it up!