I believe there may be a multitude of 'sounds' here, causing possible confusion.
The original poster quoted, I think, FL15 to FL12 (think (s)he meant 15000 to 12000 feet).
I know the aircraft that pass over my house inbound to BHX (EGBB) Birmingham are above 10000 ft so this 'air' noise is not Flap/ Slat deployment.
I am of the opionion we are talking about Deployment, or Stowing of
Speed Brakes at this level, but am just curious as to its actual source.
Last edited by mustbeaboeing; 27th August 2012 at 14:47.