French Dogs at push back?

[MakD]

I recently flew out from Toulouse and CDG in France, and both times when the aircraft (airbus) was getting pushed back by the tug there was this noise that I can only describe of being like a dog barking in the hold below as the aircraft rolled back.

What is this noise? Does the way the tug fits onto the wheel rub on something what ever it is it's pretty annoying lol.

[Tinstaafl]

Simplest explanation is that the cargo load included a dog or two.

[Human Factor]

It's a self test of the hydraulic Power Transfer Unit (PTU) which is under the floor amidships. Sounds very like a barking dog - a good reminder to turn off the PTU switch when you shut down after taxiing in on one engine and the pax mention it!!

[compressor stall]

If it was in East Asia, I would have suggested it might have been coming from the galley....

[Old Smokey]

Are you sure that they weren't American Dogs ?

Part of a Boeing plot to frighten Airbuses.