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Old 29th January 2024 | 18:03
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CaptainProp
 
Joined: Aug 2002
Posts: 1,658
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From: Up north
Originally Posted by PENKO
What exactly is the problem with manually trimming the aircraft from 200kts down to Vapp? None whatsoever for a half competent pilot!

I think you are confusing this scenario with the G+Y failure where there is actually a very good reason to be in trim before you lower the landing gear. With no G+Y pressure you loose the stabilizer trim so you want the side stick to be centered at Vapp before lowering the gear and activating direct law.
Yes, but as quoted already above the FCOM clearly states “Extend the landing gear at 200 kt to revert sooner in direct law. This provides, below 200 kt, a better pitch control than in alternate law with one elevator lost and all slats lost.” for G+Y SYS LO PR.
In this case you want to “revert sooner to direct law” for increased pitch stability.

In the case of G+Y, as you stated, you delay gear extension in order to keep auto-trim, through the elevators in ALT law, until you are fully configured (F3) and at Vapp and then put the gear down, revert to direct law and lose auto-trim.

Two different procedures for two different reasons.

CP



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