The FMC has it's own performance computer using runway length and ambient conditions it has access to temp and QNH, it obviously needs wind and runway conditions to be entered.
However it has no knowledge of obstacles or MEL/CDLs so is deemed inappropriate to use by probably all companies.
The figures can however be used as a gross error cross check against company provided figures.
Some FMCs don't compute a V1 so entering wet or dry is meaningless.
And changing the wet / dry on page 2 having entered the company figures on page 1 will lead to a TAKEOFF SPEEDS DELETED.
Last edited by CCA; 18th Jun 2016 at 09:46.