improvment : Fuel flow at mid N1

[sdlc 5]

Hi all

On the A320/321 CFM the fuel flow for medium N1 is the double of the real fuel flow (low altitude). At ~50% N1 we have 2000-2200 kg/h. This range of N1 (45-65) is used for approach and low speed fly (GD, S ect…). The result is a doubled fuel used for standard app or holding. It’s more penalizing for long approach with opposite runway like LFPO/LFPG (around 300-400 kg more).

I think the gap is due to the choice of engine parameters internally calculated instead of FS standard calculation (cfg+air).With idle and toga FF in the PRF file, the FF is linearly calculated. Maybe, the simple solution to avoid a too complex PRF file is to insert only one intermediate table for mid N1 or an "balance" function in the engine gauge code.

It's my humble opinion

Stephane