Spoiler logic on landing

[PilotTris]

Hi Guys,

Quick question.. What is the correct procedure for the spoilers on landing. I notice that when deploying the reverse, spoilers are extended as well. I have armed my speedbrakes and keep getting the 'spoilers extending' sound on the landing roll out. Should I be arming the spoilers or just leave them and let them deploy when using reverse?

I've noticed that when I arm the spoilers for landing and then touch down, the spoilers deploy and then get retracted, then deploy repeatedly, hence the sound effect I'm getting above.

If you could please let me know the correct procedure that would be great.

Thanks,

[Litjan]

Hi,

first - pilots are trained to always trigger the ground spoilers upon touchdown and in case of a rejected takeoff manually - just as a safeguard in case the automation doesn´t work. We always prided ourselves to yank the lever back before the automation could get to it.

The correct procedure for the takeoff is to leave the speedbrake lever in the stowed position. When reversers are triggered (like for an RTO), the spoilers will deploy automatically.

The correct procedure for the landing is to set the lever to ARM (and observe the green ARM light) - this will deploy the spoilers when the wheels spin up into the FLT position and then to full GROUND deploy when the strut compresses. If this does not work (like in an aquaplaning scenario) and the pilot forgets to yank it manually - the reversers will deploy the spoilers (like in the takeoff scenario).

Cheers, Jan

 

[PilotTris]

18 hours ago, Litjan said:

Hi,

first - pilots are trained to always trigger the ground spoilers upon touchdown and in case of a rejected takeoff manually - just as a safeguard in case the automation doesn´t work. We always prided ourselves to yank the lever back before the automation could get to it.

The correct procedure for the takeoff is to leave the speedbrake lever in the stowed position. When reversers are triggered (like for an RTO), the spoilers will deploy automatically.

The correct procedure for the landing is to set the lever to ARM (and observe the green ARM light) - this will deploy the spoilers when the wheels spin up into the FLT position and then to full GROUND deploy when the strut compresses. If this does not work (like in an aquaplaning scenario) and the pilot forgets to yank it manually - the reversers will deploy the spoilers (like in the takeoff scenario).

Cheers, Jan

 

Thanks Jan for a detailed response. This makes sense and I have armed the lever before landing, however on touchdown the spoilers get deployed and then get stowed. This happens repeatedly during the landing roll.. Could this be a lever issue? I'll try and do a video showing this.

Regards,

[Litjan]

The spoilers get "autostowed" if any thrust lever gets advanced past a certain point (this guarantees that they will be stowed in case of a go-around). Make sure that this is not triggered in your case by some axis assigned to "throttle"?

Edited September 26, 2021 by Litjan

[PilotTris]

13 hours ago, Litjan said:

The spoilers get "autostowed" if any thrust lever gets advanced past a certain point (this guarantees that they will be stowed in case of a go-around). Make sure that this is not triggered in your case by some axis assigned to "throttle"?

I don't believe this is the case as I'm using reverse thrust..

[Litjan]

1 hour ago, PilotTris said:

I don't believe this is the case as I'm using reverse thrust..

You are right, it is unlikely - but maybe there is some errant axis assigned to throttle?

Try to land without using reverse thrust (yes, it is against procedure, but it is possible to fly the 737 with reversers inop) - just to check if that is the problem?