Airbus Noise

Probably just the spirit of some unhappy little Frenchman trapped in the cargo hold

I just laughed out loud at that! Brillant! Then again, would it be an unhappy little German if it were an A321? 😀

Paul

Hi All,

Question for any techies out there…

I’ve noticed when I fly on Airbus aircraft (only A320s, 319s, 321s I think) that after arriving at the gate there is a loud whining sound which seems to be coming from under the cabin floor –

Andrew

Probably just the spirit of some unhappy little Frenchman trapped in the cargo hold

Thought my answer was a little too simplistic for an aviation forum. Cheers chaps for the A320 trivia!

Thanks all, that’s fantastic! Always wondered what it was for and thought that it couldn’t possibly just be the cargo doors opening!

Andrew

Ah ha Mr P back oop north at last,are you in work next week??:D

Damm, you’r quick PMN!!!!
I was about to put………

It’s the hydraulic power transfer unit operating. The Yellow and green hydraulic system has a hydraulic pump/motor unit inter connecting them. This enables one to drive the other if the difference in hydraulic between them is more than 500psi.
The left engine powers the green system and the right engine powers the yellow system. The yellow system also has an electrically driven pump. An electrically driven pump powers the Blue system
On start up this unit is tested automatically after the second engine is started for a few seconds. On engine shut down the unit will detect a low pressure in one side, get the other one to pressurize it. That will cause the other side to de-pressurize, so the first side will have a greater pressure and cause the PTU reverse and so on!
This is the “Barking” noise you heard.

Rgds Cking

P.S. Guess who just got back from an A320 course?!!!

It is the Power Transfer Unit. The PTU allows the Green and Yellow hydraulic systems to pressurise each other in the event of a Green or Yellow hydraulic pump failure.

It is inhibited when:

• One Engine Master switch is ON, the other OFF, and Parking Brake Set.
• One Engine Master switch is ON, the other OFF, and NWS Bypass Pin is installed.
• Cargo Door Operation

Yeah… Something to do with hydraulics and pressurising! 😀

Paul

I do know of a very distinctive sound heard on all the A320 series aircraft which sounds like what you’re describing. You can usually feel the floor vibrate when it happens! I usually notice it either at the gate or taxi’ing for departure although I’ve even known it to continue for a while when airborne. I believe it’s one hydraulic system pressurising the other but perhaps someone with a little more technical knowledge can confirm!

Paul

Not sure as I can’t remember hearing any strange noises on an Airbus aircraft, but from what you’re describing it sounds like cargo hold doors being opened.