Hi,
Partial extension happens only in case of assymetric touchdown and reverse selection - similar to the A320, at least current Mod.
The GND signal for full spoiler deployment comes either from wheel spin up, or (both MLG compression AND RA<6ft).
The latter takes time since MLG is double bogey and normally there's a significant delay between aft wheels touchdown, the front wheels touchdown and the oleo compression (hence usually two distinctive thumps on landing).
My theory was that reverser selection deployed spoilers before AIR/GND logic signal was processed, but I am not so sure anymore...
In any case, after reverse selection on touchdown of the aft MLG wheels two distinctive things happen:
- immediate touchdown (or rather thump!) of the front MLG wheels and oleo compression
- significant pitch-down moment which has to be counteracted by sidestick
If reverse is not selected, the pitching moment is close to neutral, similar to the A320. Perhaps the reason is loss of lift due to airflow disruption as Tdracer described... Never ever noticed any pitch-up though...
Where is A33Zab, when we need him
