How many redundant systems are there on a Commercial Airliner?

Question

How many redundancies are there on the various vital systems (Hydraulics, avionics, engine ECU, fuel pumps??)

Answer 1

Well it depends on which manufacturer of the airplane is. When you say comeercial airliners those includes new generation Boeings, Enchance Airbuses and even the old McDonnell Douglas airplaines and more.... meaning old and new planes. If this is the way your goes I would say vital systems varies from 2 to 5 redundancies depending on its reliability. You may want to ask more specific next time so that i can give you more specific answer. Glad to help.

Answer 2

Ok the second answer only applies to Airbus, and a majority of commerical aircraft in service has three systems, the first one would be the primiary system, and there would be a secondary system if the primary fails, and the third system would be an alternative means of regaining control if all two fail, a good example is the main landing gears, the primary will operate the hydraulic motors and actuators, but if the motor fails there is a secondary motor which will take over. If there is a loss of hydraulic fluid or power, there is a cable and latch system which will drop the landing gears. The majority of commerical aircraft will have minimal flying control in cable or push/pull configuation in event of electricty malfunction or hydraulic malfuntion. Which rarely happens.

Answer 3

One primary two redundant systems for hydraulics, avionics are electric so if the engine generator that powers them fails there is a little door that opens on the fusalage and a little propeller is extended into the windflow and it drives a little back up generator that produces enough juce to power the critical systems needed.