NSEU
20th Apr 2007, 22:43
The 744 has a speedbrake auto restow function (like most aircraft)... That is, if the speedbrakes are extended on the ground, and the throttles are advanced for takeoff, the speedbrake will stow, c/o the speedbrake electric actuator.
Now the what-if/idiot factor...
The throttles are advanced for takeoff.. and for some reason, the pilot decides to arm or completely deploy the speedbrake after he has advanced the throttles. I tried this at the gate a few days ago (engines off, but EEC test switches on and all hydraulics on). I expected the speedbrake lever to auto-restow in this situation also... but it doesn't. The spoilers reamained in whatever position I left them in.... On the takeoff run, I would imagine the aircraft would remain well and truly on the ground.
Can't figure out why it doesn't restow (wiring schematics are not so easy to understand).
Does the 767 operate this way also or does the fly-by-wire spoiler control keep the spoilers down?
Thanks for any insight.
Rgds.
NSEU.
P.S. (Edit) Sorry, just noticed this thread....http://www.pprune.org/forums/showthread.php?t=106016 I see that the auto-restow requires the spoilers to have been automatically extended.
Now the what-if/idiot factor...
The throttles are advanced for takeoff.. and for some reason, the pilot decides to arm or completely deploy the speedbrake after he has advanced the throttles. I tried this at the gate a few days ago (engines off, but EEC test switches on and all hydraulics on). I expected the speedbrake lever to auto-restow in this situation also... but it doesn't. The spoilers reamained in whatever position I left them in.... On the takeoff run, I would imagine the aircraft would remain well and truly on the ground.
Can't figure out why it doesn't restow (wiring schematics are not so easy to understand).
Does the 767 operate this way also or does the fly-by-wire spoiler control keep the spoilers down?
Thanks for any insight.
Rgds.
NSEU.
P.S. (Edit) Sorry, just noticed this thread....http://www.pprune.org/forums/showthread.php?t=106016 I see that the auto-restow requires the spoilers to have been automatically extended.