masonaries
Posts: 91
Joined: Thu Jun 08, 2000 11:10 pm

Airbus A319/320 Question

Mon Dec 13, 2004 2:58 am

Pardon my ignorance but what is the noise these aircraft make as they are about to pull away from the gate? It sounds like a drill is tightening something below deck. Are they locking down the luggage compartment? Just wondering.

Bondo
 
Leskova
Posts: 5547
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RE: Airbus A319/320 Question

Mon Dec 13, 2004 3:10 am

I think the answers that are given in this thread should explain what you were hearing...

http://www.airliners.net/discussions/tech_ops/read.main/93654

Regards,
Frank
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UALFAson
Posts: 766
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RE: Airbus A319/320 Question

Mon Dec 13, 2004 3:10 am

I think what you are probably hearing are the luggage bin doors closing. Yes, they are very loud and probably scary sounding to pax who aren't frequent flyers.

You may also hear a knocking noise during taxi. I've been told that's the hydraulics of the plane.

Noisy on the ground, but a smooth flyer (please no A vs. B flaming!)
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NWB757300
Posts: 135
Joined: Sun Apr 25, 2004 6:47 am

RE: Airbus A319/320 Question

Mon Dec 13, 2004 3:12 am

As was explained to me in the Tech/Ops forum, the sound is the Power transfer unit (PTU), where the (i believe) green and blue hydraulic systems power each other if they have a large difference in psi.

Hope this helps but tech/ops may be more informative...
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Starlionblue
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RE: Airbus A319/320 Question

Mon Dec 13, 2004 6:22 am

As I have explained repeatedly: It's them darned raccoons.  Smile
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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longhauler
Posts: 4948
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RE: Airbus A319/320 Question

Mon Dec 13, 2004 10:29 am

Close NWB757300:

Just as the second engine (engine 1) is starting, but before it reaches idle, the hydraulic system goes through a test. The PTU is tested by using the Yellow system power (powered by the engine 2 hydraulic pump) to power the Green system before engine 1 reaches idle.

When engine 1 reaches idle, then the Green system is powered by the engine driven pump, and the PTU shuts down.

The sound you hear when the cargo doors are closing, is the auxiliary Yellow pump. The cargo doors are Yellow hydraulic powered, and this auxiliary yellow pump, (like the PTU) is located under the cabin, mid fuselage. When a cargo door is opened or closed, you will hear this pump start/stop.
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