Engines ratings and takeoff performance

[LeCoyote]

Hi Denti,

Interesting... Let me see if I get this right: you look up your tables, and at some point the N-1 climb gradient does not allow you to clear the obstacles, so you use the next available thrust rating (be it assumed temp or derate), or something like that ?

What would be the climb gradient in that case ? I work at LFPG, where the airport is surrounded by flat fields, so obstacles are not really a problem usually. This is the reason why I am asking about this.

At any rate (no pun intended...), I assume that this would happen when you have an obstacle that reaches higher than the usual, obstacle-free 1.9%, right ? Or am I still missing something here ?

Cheers,

LeCoyote