Recently got into a debate with a few co-workers and we were not able to come to a conclusion do to lack of resources. Will the rudder trim remain operative with a loss of sys a and b hydraulics with the standby rudder active?
As long as you have electrical inputs for your rudder trim and an hydr source(stby is one),the rudder trim will power the pcu which will use the stby hydr press to move the rudder.
are the aileron trim usable when the Sys A and B fail?
The ailerons trim SWITCHES will work but the electrical input from these switches will not move the ailerons without hydraulic pressure.
So NO.
With A and B system hydraulics inop, you'll still have rudder and elevator trim
Rudder trim is working the same way as the aileron trim,electric input but hydr pressure is necessary for the pcu to move the rudder.Standby hydr is there for that reason.
Elevator trim?you mean elevator balance tabs? They are mechanical so they will help in offloading elevator forces during manual reversion.
The stabiliser trim can be electrical via the switches or manual via the handles,in any case hudraulic pressure is not needed to operate the stabiliser.