Interestingly, starting at FLAP 10, there is a decrease in max TO weight allowed. Which seems to be in contradiction with some of Jack's comments (lots of fuel, lots of passengers). So, my understanding is FLAP 25 will be used on a VERY short runway, with SOME restrictions on payload (and of course with no obstacles in the path, since climb angle will be shallow). Looking at the tables, on a dry runway, for a given weight, going from FLAP 1 to FLAP 25 allows to lower Vr by 9 to 15 kts, depending on model. Anyone disagrees with that?Bruno

I seem to recall taking off from Lihue PHLI RW03 at MGTOW, loaded to the gills with fuel. That was 1.5 years ago, so my memory wanes a bit. Maybe that takeoff is not very restrictive on MTOW because as soon as you clear the palm trees (if you palm trees . . . ) you're over the Pacific. Of course, we also only operated at about 2330 in the night, so it was nice and cool, too.In other words, I'm not sure you lose available TOW if you don't have obstacles.

I seem to recall taking off from Lihue PHLI RW03 at MGTOW, loaded to the gills with fuel. That was 1.5 years ago, so my memory wanes a bit. Maybe that takeoff is not very restrictive on MTOW because as soon as you clear the palm trees (if you palm trees . . . ) you're over the Pacific. Of course, we also only operated at about 2330 in the night, so it was nice and cool, too.In other words, I'm not sure you lose available TOW if you don't have obstacles.

You can pull those "stunts" at MSL, start going up and the scenario starts to shift.