Originally Posted by
Allegra1986
Possibly, what would that be for? The noise reoccured when we were accelerating and climbing slightly near landing too but only briefly, whereas during take off it lasted about 5/10 minutes. Would you ever find out if something had gone wrong on the plane if it wasn't obvious to the passengers (not that i'm suggesting it did, just curious)?
I was only guessing that it might have been the PTU based on your description of 'chainsaw noise', but since it happened during take off (I didn't read your post properly the first time - sorry!), it might not have been the PTU. In any case hydraulics on aeroplane relate to a lot of items. But even if it was the engine (they can also make some silly noises as well), it's extremely unlikely that there was anything substantially wrong with it.
If it was something serious, they would have returned to land instead of carrying onto LHR, so you would have found out. The pilots have all sorts of instrument monitoring the engines and other aircraft systems. It's extremely unlikely that there was anything seriously wrong with it, if anything at all.