PPRuNe Forums - View Single Post - THS in the Airbus A320/21/19...
View Single Post
Old 5th Apr 2018, 06:33
  #4 (permalink)  
Uplinker
 
Join Date: Nov 1999
Location: UK
Posts: 2,524
Received 127 Likes on 81 Posts
The actual physical turning of the screw jack that moves the THS is performed by two hydraulic motors, one powered by the green system, the other by the yellow. The trim wheel is a control only - it cannot turn the screwjack itself. So you need green or yellow hydraulics, (usually both). So you need at least one engine running.

I suppose that in theory you could move the THS with the yellow electric pump pressurising the yellow system, but I never tried it and don’t know if there is a system restriction against this.
Uplinker is offline