Airbus A319 question for the experts!

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Airbus A319 question for the experts!

Postby jimclarke » Tue Aug 09, 2011 10:57 pm

Very recently I made a couple flights (for real) in an Airbus A319.  My question is what is the weird noise the plane is making as it is being pushed back and starting to taxi?  It is a rhythmic muffled "barking" noise which seemed to last a couple minutes. Maybe hydraulics?
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Re: Airbus A319 question for the experts!

Postby tcco94 » Tue Aug 09, 2011 11:57 pm

Most likely the PTU (Power Transfer Unit)...
http://en.wikipedia.org/wiki/Power_Transfer_Unit
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Re: Airbus A319 question for the experts!

Postby GlobalHobo » Wed Aug 10, 2011 12:25 am

It is indeed the PTU, or Power Transfer Unit. There are three hydraulic systems in the aircraft. One is powered by an engine-driven pump and an electric pump, one an engine-driven pump only, and one an electric pump only (and a Ram Air Turbine, or RAT, in the event of a total electrical failure). The PTU provides pressure to the system with only the engine drive pump from one that is driven by an electric pump when ever the engine is not operating, such as on the ground before engine start or after shutdown, or during an engine failure in flight.

You won't hear that in a Boeing, because each system has both an engine-driven and an electric pump. But the DC-10 had a system very similar to the Airbus which was retrofit to all aircraft after the Sioux City United crash to preclude the total loss of hydraulics in the event of a catastrophic failure.

Probably more info than you really wanted to know. Class is in session
Last edited by GlobalHobo on Wed Aug 10, 2011 12:29 am, edited 1 time in total.
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Re: Airbus A319 question for the experts!

Postby expat » Wed Aug 10, 2011 9:16 am

You won't hear that in a Boeing, because each system has both an engine-driven and an electric pump.



And if you do hear it in a Boeing, start to be mildly concerned because you have just lost an engine on take off..............

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Re: Airbus A319 question for the experts!

Postby jimclarke » Wed Aug 10, 2011 11:38 pm

Thanks for the information! Fortunately I didn't hear that in the Boeing 737 we flew in earlier. ;)
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Re: Airbus A319 question for the experts!

Postby expat » Thu Aug 11, 2011 6:17 am

Thanks for the information! Fortunately I didn't hear that in the Boeing 737 we flew in earlier. ;)



Remember, it is not the fall the kills you, it's stopping that does it  :-X

Matt
"A bit of a pickle" - British translation: A catastrophically bad situation with potentially fatal consequences.

PETA Image People Eating Tasty Animals.

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1. Captain, if the problem is not entered into the technical logbook.........then the aircraft does not have a problem.
2. And, if you have time to write the fault on a napkin and attach to it to the yoke.........you have time to write it in the tech log....see point 1.
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Re: Airbus A319 question for the experts!

Postby 1olehippy » Thu Aug 11, 2011 11:28 am

My question is what is the weird noise the plane is making as it is being pushed back and starting to taxi?


That's why we affectionately refer to them as a "ScareBus"

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