A 320 question
 

A320 question: Is the ground spoiler inhibitor circuit keyed to wheel spin, and, is there a manual reversion mode if ice or other conditions keep wheel spin below the threshold? Is there no role for the squat switch?

Hi!

If I read my FCOM right you get also get spoiler spoiler extension if RA is less than 6 feet and both MLG are compressed.

Partial spoiler extension if at least one thrust lever in reverse with the other at idle and one MLG compressed.

BR

Buster

A320
 

Thanks

That seems to say that wheel spin doesn't enter into the deployment

Is that correct?

No, it's not. Busterpilot's answer is correct but incomplete.

Wheel speed is one of the logic conditions for GND SPLRS extension.

Inhibition is also keyed to wheel speed: you have inhibition between lift off and return of wheel speed below 23 kts or touchdown.
(touchdown condition= wheel speed>72 kts OR both MLG compressed and RA<6ft).

Proximity Detectors on Shock absorbers (I guess what you referred as "squat switch") will deliver the compression condition to the LGCIUs, so they have an important role.

(Ref: FCOM 1.27.10 p 12/13 and AMM 27.90.00 p26).

That said, Airbus recently modified the ground spoiler logic (new SEC standard 120 to cope with inappropriate TL position during flare...), but as far as I remember the wheel speed logic remained unchanged.

If you bounce a landing the spoilers stay extended but would retract if TOGA was applied for a go around. Correct ?

It's correct indeed

Thanks for clearing that up. :ok:

FCOM 1.27.10 p13 - shows an OR gate

Wheel speed above 72 kts
OR
MLG compressed.

Manual reversion: not for ground spoilers, but speedbrakes work if NOT in CONF FULL.
It's all in the books....