View Full Version : Strange Noises heard on various aircraft - What are they?

Dont Hang Up
21st May 2008, 12:42
Just flown (as SLF) A320 out and A319 back from Frankfurt.On both flights, immediately after engine shut down there was a load noise that I can only describe as a giant trying to rub a stubborn stain off the tail of the aircraft with an enormous chamois leather! It went on for quite a while gradualy getting slower as though the said giant was becoming exhausted. I fly quite a bit but this sound is something I cannot place. Explanation from those that know much appreciated.

21st May 2008, 13:01
Probably the Power Transfer Unit. See also "Barking dog noise"...
Something to do with supplying hydraulic pressure once hydraulic pressure reaches a certain level, due to an engine being shut down.

21st May 2008, 20:32
I asked an A320 type-rated AME exactly the same question about 2 weeks ago....and he said;


So that's 2 votes for that answer.

22nd May 2008, 11:30
On the A330 / A340, if it is hot and humid, 'smoke' (actually a fog of condensed water) pours out of the air-conditioning vents immediately after take-off, accompanied by loud bangs and crashes from somewhere in the ceiling. Made my heart beat that little bit faster the first time and have seen people get really panicky. Maybe expand this thread to include 'unsettling' noises on planes?

Dont Hang Up
22nd May 2008, 12:18
'Maybe expand this thread to include 'unsettling' noises on planes?'
In which case, how about the sound of the 146/RJ putting in the first stage of flaps? In the cabin it gives a loud roar of descending pitch that makes me think of the gates of hell swinging open.

23rd May 2008, 01:40
What about the "buzz saw" on Airbus 319/320 aircraft during takeoff and climb? This was discussed here before and I recall pilots writing, "Yeah, that is the buzz saw" but not much else. Did I see somewhere it was fuel pump noise?

23rd May 2008, 03:32
Dont Hang Up - hope you don't mind. I have changed the title of your thread to a more generic version, and will now include this thread in the forum FAQ.

Final 3 Greens
23rd May 2008, 05:54
accompanied by loud bangs and crashes from somewhere in the ceiling.

Sounds like pieces of ice exiting from the air con packs.

You can replicate the experience on your home a/c if you set it to a very low temp and then leave the windows open :eek: