A320 THS drive question
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Joined: Jan 2006
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From: Between a rock and a hard place
A320 THS drive question
Doing my A320 rating... 10 yrs after the majority of Pprune users it seems 
The CBT uses (to me) odd wording describing the THS drive: the hydraulic motors are driven by one of three electric motors.
Having read and listened over and over again, I interpret it as electric motors position control valves deciding direction of rotation of the hydraulic motors, but It's still the hydraulics that drive the hydraulic motors that run the jackscrew? Is this correct? For manual trim the control valves are positioned mechanically, and we still need hydraulics to run the THS?
The CBT uses (to me) odd wording describing the THS drive: the hydraulic motors are driven by one of three electric motors.
Having read and listened over and over again, I interpret it as electric motors position control valves deciding direction of rotation of the hydraulic motors, but It's still the hydraulics that drive the hydraulic motors that run the jackscrew? Is this correct? For manual trim the control valves are positioned mechanically, and we still need hydraulics to run the THS?
Joined: Nov 1999
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From: UK
Yes, you need green or yellow hydraulics to actually move the THS. The electric motors only effect control of the hydraulic motors; not sure exactly how, but without hydraulics, the THS cannot move.
Joined: Jun 2007
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From: Wanderlust
Doing my A320 rating... 10 yrs after the majority of Pprune users it seems
The CBT uses (to me) odd wording describing the THS drive: the hydraulic motors are driven by one of three electric motors.
Having read and listened over and over again, I interpret it as electric motors position control valves deciding direction of rotation of the hydraulic motors, but It's still the hydraulics that drive the hydraulic motors that run the jackscrew? Is this correct? For manual trim the control valves are positioned mechanically, and we still need hydraulics to run the THS?
The CBT uses (to me) odd wording describing the THS drive: the hydraulic motors are driven by one of three electric motors.
Having read and listened over and over again, I interpret it as electric motors position control valves deciding direction of rotation of the hydraulic motors, but It's still the hydraulics that drive the hydraulic motors that run the jackscrew? Is this correct? For manual trim the control valves are positioned mechanically, and we still need hydraulics to run the THS?
Joined: Nov 1999
Aviation Qualifications: ATPL
Posts: 3,150
Likes: 744
From: UK
Just to add; IF you are having a very bad day and have lost both green and yellow hydraulics, you will have lost the THS movement, but you will still have both elevators from the blue hydraulic system. So you retain some pitch control.
Thread Starter
Joined: Jan 2006
Aviation Qualifications: CPL
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From: Between a rock and a hard place
I think I am practicing for my Air Force career will all these F/CTL computers! Except the protections seem to be somewhat restricting me 
