A320 'oilcan' noise
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?