A320 questions...
 

What is the noise of what sounds like a chap using a hacksaw in the hold, before and after flight?

and twice now I've heard the same noise sitting over the wing as we rotated which sounded very much like an engine surging, but not as loud. Something to do with the gear braking or retracting?


Cheers

Power transfer unit - Wikipedia, the free encyclopedia

Unlikely it was at rotation unless it did actually have a failure. Did you land back at the same airport, if not it was not the guy with the hacksaw you heard on rotation but something else I have no idea about. If it was shortly after rotation I expect the pressure dropped in the green (not sure if A320 but probably) system and the PTU operated whilst the gear was brought up.

I suspect this is the hydraulics running as they close/open the hold doors.
After t/o probably still hydraulics with the gear retract.

Hacksaw noise (sometimes described as dog barking) = Power transfer unit, as previously mentioned

Quiet "surge" noise - if a muffled bang that lasts very little time then possibly the main gear oleos reaching full extension as the a/c weight lifts off them. If a more rapid shuddering noise which lasts a longer time then possibly some vibration from the wheels as they retract.

Regards
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