A320 'oilcan' noise

[lunkenheimer]

Flew on a United A320 last week which made a strange sound during taxiing. At first I thought it was a lose link in the U/C making a clunk, but then I recognized the sound as a panel 'oilcanning' i.e. a nearly flat panel with a small distortion that pops back and forth between one shape and another like the bottom of an old-fashioned oil can as stress changes direction.

I was seated 4 rows behind the overwing emergency exits, and the sound was coming from below me. It was quite loud and distinct.

Is this something normal for an A320?

[snooky]

I've heard this from the same position. It seemed to coincide with brake applications, so I assumed that the noise was being made by a valve in the braking system.

[Roadtrip]

What do you think the skins of airbusses are made of anyway?

[moleslayer]

Pax sitting around that area often comment on this noise.
It's either the brake system shuttle valve operating, which makes a kind of 'clonking' sound. Or if taxiing single engine, the Hydraulic PTU (power transmission unit) may be running, this sounds more like a 'whining noise', starts off low down & builds up to a crescendo, then stops, then repeats the whole process over again & again.

[lunkenheimer]

The shuttle valve could be it; I only heard the noise during low speed taxiing. I didn't hear it during either takeoff roll (two segments in the same aircraft), nor rollout.

[777AV8R]

Definitely scary stuff...Boeings don't do that....I was wondering why all the oil companys went to plastic containers..Airbus bought all the tin.

[Young Paul]

777 - Tch, scaremonger. All aeroplanes make scary noises when you don't know what's going on. It's when they make scary noises when you thought you did know what's going on that's more worrying.