Chris Scott,
Thanks a lot, great explanation! But still can`t get it why after all calculations "with clearway" option gave me a lower TO weight than "without clearway". It should be the opposite. I understand that with clearway speed decrement is greater than without clearway, but the weight decrement shouldn`t.
Strange... Ohh well, performance has so many "grey" issues!
Most airlines do not account for clearway on takeoff for wet or contaminated runways... obviouslly 15ft at the threshold is already quite low, using a clearway would reduce that margin for almost nothing increasing the risk of not being airborne at all at the end of the runway.
But the airline where I`m working for has no policy regarding that and regulations have nothing about it either (at least that I know).
But I remember when I flew the 737 some years ago I belive the FCTM recommended not using the clearway for wet runways.
Oh and I learned something new... I didn`t know that CARs allowed no weight reduction for wet runways... First time I hear that, I wonder if many more countries allow that.
Henry, you`re right, its 15ft not 35.
Thank you guys