Originally Posted by
eagleflyer
PEI, but where does hydraulic power come from when all engines have failed and the APU doesn´t run due to lack of fuel? I understand it would come from an electrical pump that would run on battery power (the only energy source left). How long would that battery last?
Why does that matter ?
The only powered primary flight control on the 146/RJ is the rudder; elevators and ailerons are controlled via conventional servo-tabs and will function perfectly well in the absence of hydraulic power.