Originally Posted by
Tu.114
About the engines and their connection to the hydraulic pumps, as the question was asked: On a PW120, the hydraulic pump is mounted on the propeller reduction gear box along with the variable frequency AC generator and other things. The turbomachinery drives the DC starter generator that generally speaking provides the low(er) watt systems. If one propeller is feathered and the other is running, the good engine will provide power to the failed engines hydraulic system in some way (be it via an AC electric auxiliary pump or a unidirectional PTU), but with all engines feathered, hydraulics will generally end up unpressurised, whether or not the turbomachinery is still running.
You are mixing up Dash8-400 (PW150) and ATR 72 (PW124&127) again.
On theATR there is no hydraulic coming from the engine.
The hydraulic pumps are electrical driven and located in the belly.If one engine is running with Np above 66% both ACW buses are supplied and both hydraulic pumps are running.