Dunno what the hell the noises are but it was mentioned in another thread about Airbus vs Boeing.
Find the A340 in particular very noisy on long haul flights and the temp vary wildly throughout the cabin.
On a flight to Santiago recently it sounded like the hound of the baskervilles!
A few years ago on a flight to Cairo with Air Egypt they couldnt cool down First/Business Class and we had to swelter.
No reasons supplied.
To make matters worse have you heard the hydraulic noises mid cabin in those babies???
Sounded like grinding metal or someone trying to kill the Baskerville pooch!
No wonder they went through phases of hydraulic pumps catching fire and burning the aircraft into two pieces on the ground whilst under tow.
Really instills confidence.
As for the other manufacturers they aint saints either with Capton wiring fires and fuel pump hassles etc.
Havent yet had the honour of riding the A330 but I can tell you I quiver with anticipation..............
Beats a Tupolev/Illyushin or Yak anyday though.