A320 Mechanical Backup
 

Greetings all,

My understanding is that hydraulic power is required to control the rudder and manual stab wheel inputs during mechanical backup ops. I tried it in the sim with all three hydraulic systems depressurized and there was no change in handling, is this correct or a sim fault?

Many thanks

Your understanding is correct. Sim fault.

Seconded.

Were the hydraulics actually depressurised or had you only just turned the pumps off - meaning there was residual pressure? There are probably accumulators in the system - to improve control and smooth out pump responses - that pilots are not told about.

Yellow or Green hydraulic power is needed to move the THS,
Yellow or Green or Blue for the rudder.

All three systems depressurized indicating zero on the HYD system display..

Then you do not have any Flight Controls left. At least one Hydraulic Power Source is needed even for mechanical backup.

It's just the input which is mechanical but not the actuation which is hydraulic for every flight-control in every case.