Firewall engines with 22k derate (B738)

[PitotTube]

Hello,

If engines have been derated from 26k to 22k for takeoff and windshear is encounterd just after takeoff and engines are firewalled, does the engine give max power there is for the engine then (27K bump/26k), or does it provide max 22k power?

thanks, pt

[BOAC]

http://www.pprune.org/forums/showthread.php?t=229653 discusses this too.

[Michael1282]

You have to distinguish between fix derates and TO derates.
Fix derates are accomplished by changes to the HMU or EEC.
A TO derate is simply selected in the FMC ( I think not every operaror has this configuration)
When firewalling a TO derated engine (e.g. 27K to 25K) you get 27K.
Firewalling a fix derated engine has no effect on the rated thrust.

(B737)

Please correct me if I am wrong.

Michael

[Dehavillanddriver]

For a 700 if you push the levers to the firewall you get 24k regardless of what you paid for.

For a 800 you get 27k regardless of what you paid for.