spolier cant be used on take off

[soul112 0]

hey all, so this happend a few years ago when i was going thru the checklist all is good to go. advanced the thottles and then alarms ! it says speedbreak extended, but its just armed for take off. i dnt arm the SB anymore cos i know the outcome. but can this be fixed ?

 

alex b

[Blue_Ice 1]

I think you'll find that speed  brakes should be armed for landing, not for take off. The spoiler will deploy automatically in the event of a rto.

[KriVa 307]

You don't happen to fly the MD-11 rather often, do you?

[Lawyer+Pilot 126]

Arming the speedbrake tells the aircraft to deploy the spoilers when the weight on wheels sensors trip. I believe the throttles have to be at idle as well, but I could be thinking of another aircraft. Point being you don't arm the speedbrake for takeoff--only landing.

[dmwalker 604]

I think I read that, with Airbus, you arm the speedbrakes for takeoff but, with Boeing, you don't. Could that be correct?

[soul112 0]

ah cheers. had it in my mind tht were armed just incase of engine failor or other emergence. with auto brake.

 

akex b

[Qavion 19]

Arming the speedbrake tells the aircraft to deploy the spoilers when the weight on wheels sensors trip. I believe the throttles have to be at idle as well, but I could be thinking of another aircraft. Point being you don't arm the speedbrake for takeoff--only landing.

 

Correct. Both thrust levers 1 and 4 need to be retarded for the speedbrake lever to auto-deploy (from the ARM position). Either 1 or 4 thrust levers advanced will restow the lever. Aircraft must be on ground and hydraulics 1 & 4 pressurised, although, on some 744's, you can pull circuit breakers to simulate hydraulic pressure. However, without hydraulics, the spoiler panels will not move.

 

Cheers

Ian Riddell

[XPX64man 130]

I believe, like he said, that the MD80 and the Airbus both arm the spoilers before takeoff.

When the spoilers deploy during a rejected takeoff, they will add downward pressure to the wheels making the brakes more effective for a safe stop.

Boeing doesn't buy the idea.

[Lawyer+Pilot 126]

I believe, like he said, that the MD80 and the Airbus both arm the spoilers before takeoff.

When the spoilers deploy during a rejected takeoff, they will add downward pressure to the wheels making the brakes more effective for a safe stop.

Boeing doesn't buy the idea.

I wouldn't say Boeing doesn't buy the idea. They just made spoiler deployment automatic in a rejected takeoff.

[XPX64man 130]

I wouldn't say Boeing doesn't buy the idea. They just made spoiler deployment automatic in a rejected takeoff.

 

Oh, I didn't realize that!  Thanks.

[Qavion 19]

Semi-automatic  You still have to lift the reverse thrust levers to activate the speedbrakes during an RTO.

 

Cheers

Ian Riddell

[hopskip 253]

Correct. Autobreak set to RTO + AND + Thrust reversers opened to at least idle reverse = Speebrake/Spoiler deploys to full open.

 

So Takeoff configuration is Speedbrake Lever full forward/closed/not armed.

 

MD11, MD80, A3xx takeoff configuration is Speedbreak armed.

[Qavion 19]

Actually, the Autobrake is not required for autospeedbrake deployment. Only hydraulics, electrics, aircraft on ground, and reversers are required (idle thrust has to be set to get the reverse levers up, due mechanical interlocks).

 

Moving the reverser levers mechanically lifts the Speedbrake Lever up (out of the DN detent). This activates the autospeedbrake electrical circuit (independent of the ARM circuit).

 

Cheers

Ian Riddell