Re: DC-9 Flight Control

From:         "Brad Gillies" <>
Organization: Internex Online (, Toronto, Ontario, Canada
Date:         01 Jun 96 16:27:13 
References:   1 2
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>The description for the L-1011 also shows that the hydraulic systems are
>generally "re-configurable" to a certain extent. For example, if one engine
>shuts down, the hydraulic system it powers can be powered by another engine
>via a transfer pump.  Some aircraft provide an electrical pump as a backup,
>and usually the APU can provide hydraulic power, or even a ram-air driven
>turbine can power a system in the event that none of the engines nor the
>APU are functioning and the plane is gliding.

I Have yet to see any commercial transport aircraft from the DC-9 up to
the 747 that has a Hydraulic pump on the APU.  The APU only supplies
Electrical power and Pneumatics.  The hydraulic power would come from an
electric pump somewhere else on the aircraft.