Secrets behind scary plane noises during flight revealed!

Author of the book 'Cockpit Confidential' Patrick Smith has unraveled the mystery behind the strange noises that normally emanate on planes.

Smith, who is airline pilot, revealed that the high-pitched whine and the noise like a very agitated dog might make, results from a device called the power transfer unit, or PTU, which is designed to ensure adequate hydraulic pressures during single-engine operations as it is routine to shut off one engine sometimes to conserve fuel, the Daily Telegraph reported.

He added that the noise, which sometimes continues even when both engines are up and running pertains to engine Airbus models like the A320 series, subvariants A319 and A321 and larger A330.