Originally Posted by
nitpicker330
Nothing to worry about, you should have heard the BAE146 air noise/vibration during Flap retraction!! It may have been really quiet outside but it sure wasn't inside!!
Ah, this old chestnut. It isn't (present tense, for the 146 is still very much with us) that quiet outside either. If you are on Stratford railway station, on the downwind leg of the departure circuit out of London City, the sound of flap retraction can be heard as a 146 passes overhead at 3,000 feet. I do wonder if it will be audible on television when the 2012 Olympics are broadcast, as the stadium is directly underneath.
It's an aerodynamic flow between the flap inner edge and the airframe, and was apparently a surprise to BAe on the first test flight. They developed a modification to overcome it, but it weighs over 100 kg, equal to two passengers, so nobody took it up. I did hear cabin crew say it was a convenient alternative signal that they can start service.