THERE’S a reason passengers might hear a “barking” noise during a long flight – and it’s got nothing to do with dogs. During a flight an aeroplane might make various strange noises which might unsettle nervous fliers but invariably they are nothing to worry about. The sounds are just part of the aircraft’s normal operation and knowing about them can help ease any concerns a flier might have and help them relax and enjoy the flight.
The “barking” you might hear is unlikely to be coming from a real dog but rather a mechanical barking sound that has an element of whirring in it. This sound is specific to Airbus planes, according to Travel and Leisure . Former pilot Dan Bubb, a professor at the University of Nevada , Las Vegas , said: "That barking sound on Airbus aircraft comes from the Power Transfer Unit.
Pilot Patrick Smith explained in his book Cockpit Confidential why it was only Airbus aircraft that made this noise, writing: " Boeing aircraft also employ a PTU, but the operation is slightly different and it doesn’t bark like a dog.” There are some other noises you might want to familiarise yourself with so you don’t become unnecessarily worried. A whirring sound can invariably heard before take-off – this is just the plane’s flaps – the panels on the wings – being extended.
This modifies the shape of the wing to give the aeroplane more lift at lower speeds. If you look at the wings when you can here the noise you’ll be able to see the flaps .