Anyone got any thoughts about the wizard wheeze of taxiing to the runway on 1 engine only.
It is obvious in an Airbus as the power transfer unit kicks in because it thinks the engine is being shut down and now is the time to make the sawing noise. No doubt other aircraft are doing this as well, but aren't making the noise. It stops when the idling engine is brought back on line at take off.
Shoot me down in flames if I am wrong, but how does the pilot monitor the efficiency of an idling jet just before take off? The noise worries some nervous passengers, and explanation comes there none from the cockpit.