Old Aug 9, 13, 8:44 am
  #14  
CLTmech
 
Join Date: Oct 2010
Location: CLT
Posts: 181
Originally Posted by TimesTwo View Post
Don't planes have backup hydraulics? I was on a flight from PHX - YVR earlier this year and we had to stop in SEA to change planes because of failed hydraulics. The captain sounded annoyed that he was forced to land 20 minutes before we would've reached our intended destination.
Yes and no. There are usually 2 or 3 separate hydraulic systems and redundancy come from how the systems may be routed to various hydraulic powered systems (flight controls, brakes, etc).

Using the CRJ series as an example; there are 3 independent systems, but do not have cross-pressurization capability from system to system. All three systems are linked to the elevators/rudder, and 2 are linked to each aileron. Spoilers and brakes are split between systems so any one pair has a single supply. Remaining items are single system supplied.
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