Originally Posted by
tybin
To summarize the thread:
1) Critical hydraulic systems are pressurized by RAT(s) after loosing all engine power
2) Unless specified, there usually isn't any auxillary mechanical system that could help in case of loosing hydraulic pressure and/or engine power at the same time
3) Unless the engine was badly damaged and stopped turning completely, it provides some power from windmilling
Thanks!
Your summary is not really correct. Each different type of aircraft may have different backup systems. You have to be aircraft specific. Many aircraft have a mechanical backup like the 727. The MD-80 series are mechanical all the time.