What the terrifying noises you hear when flying REALLY mean

These noises you hear on are plane shouldn't worry you

EVERY whirr, whizz, pop, click, thud and thump – EXPLAINED.

 

Nervous flyers are known to over-analyse every little bump, click and whirr they hear while flying.

"What was that?," fretting flyers will ask calmer friends, "is it supposed to make that noise?"

Luckily two aviation experts have answered all your burning questions and revealed which noises are routine – and which should have you sprinting towards the emergency exit.

The former Boeing employees revealed a behind-the-scenes look at aviation and the noises that come with it on a Quora.com online forum.

"The logical assumption is that everything on an aeroplane – the bins, seating sections, loos and galleys – is 'bolted down'," said mechanical engineer Marc Levy.

 

Passengers can often hear a high pitched noise when they board

But rather than being tightened and immobile, the overhead luggage bins "hang from a sets of tie rods", toilets and aisles "are mounted to tracks in the floor."

This means that with any movement inside the aeroplane, "all the stuff on the inside is going to adjust and sometimes bump into things."

Think of it like settling cracks in a house, or something thudding in the boot of your car as you accelerate down the slip road onto a motorway.

Marc Levy and Mike Leary, who also claims to have previously worked with Boeing, then provided a simple run-down of some of the noises you can expect to hear while travelling by air.

For example, the low humming noise that rumbles through the plane as you board is caused by the auxiliary power unit at the back of the plane.

Mr Leary explains, "That baby hums along while you are boarding the plane to keep every thing up and running while the main engines are off.

"In addition, most airports hook the plane up to the ground units to pump air and electricity into the plane to save money."

When the doors close, the pilot will switch from the auxiliary power unit to the main engine.

 

When a passenger hears a noise and thinks it means danger, they will be wrong 99.999 percent of the time

Tom Bunn

This switch can cause the lights to flicker, as well as the shudder, the "whine of the spin-up and then the ignition as it fires up" before the roar of the engine kicking in.

Airbus passengers might hear a "prolonged whine" while the aeroplane is still parked next to the gate. 

“It's from an electric hydraulic pump used to open and close the cargo doors,” reveals Mr Leary.

"It also might be reassuring for you to know, each of the pilots has an exact model of the airplane they are flying as a simulator they have to train on. 

"While in that, the trainers turn off motors suddenly, have electrical systems fail, rudders not work – everything imaginable go wrong and the pilots have to land it safely or they fail. 

"Your guys passed flight safety."

Passengers will hear plenty of noises during the flight

 

Just before take-off, the pilot flicks a switch to extend the wings wider than usual

Just before take-off, the pilot flicks a switch to extend the wings wider than usual.

“Those are flaps which make a whirring sound,” adds Mr Leary.

Those sitting close to the wings will be able to see the hydraulic flaps extending down, ready to provide the lift need to get airborne.

Then when it is time to take-off you will hear the belly roar of the plane engines.

Mr Leary explains the take-off in depth: "So now you hear the engines rev up and feel the push into your seat from moving forward. 

"You’ll be able to tell if a wheel is a little out of round because the bump of the tar strips mingle with the speed of the spinning wheels as they speed up and go blump, blump, blump.

"It always is a game I play to see how fast the aircraft needs to go before it can “plane” into the air. 

"When it goes fast, the air gets thick and acts like water. Like sticking your hand out of the car window at 60 MPH. 

"The airplane has to go at least a hundred miles an hour before it can bite into the air.

"The pilot is watching a gauge which tells him exactly what it is. When it is just the right moment, he pulls back the control yoke and the nose wheel will spin like crazy. 

"Then he pulls a little farther and you will hear both wing wheels come off the runway and spin like mad, but you won’t hear that slap any more.

"Now you will hear some of those small electric motors as the wheels are pulled up into the plane and the snap of the doors closing, first one then the other. 

"It will get noticeably quieter immediately. Now another whine as the pilot doesn’t need the big wing for takeoff any more, he will bring the flaps back into their normal place. 

"All that is called cleaning up the plane so it is smooth and streamlined.

"Now the engines are quieted down as they settle into gaining altitude while ground control tells them what direction to fly, making sure no one else is around your airplane. 

"Next, the stewards get busy to make your flight pleasant as they can by serving you. Settle back and sleep or enjoy a view relatively few in the world ever get to experience."

When its time to land, the noises will start again.

 

When full flaps are used for landing there's often a rumbling noise

Airline pilot turned licensed therapist Tom Bunn explains the landing procedure.

"When the flaps are retracted after takeoff (or extended for landing), there may be noise; on most planes, it sounds like a blender running for four seconds,” explains Bunn, who now helps people scared of flying to overcome their fear.

"There may be a brief rumbling sound when the flaps change position, as the change in flap position changes the air flow. 

"On large airliners, when full flaps are used for landing (most landings use less than full flaps), the flaps cause a continuous rumbling sound. 

"All these sounds are normal."

In fact, Mr Bunn says the only sound you should be scared of when flying, is the sound of the crew freaking out.

"When a passenger hears a noise and thinks it means danger, they will be wrong 99.999 percent of the time," he adds.

"In that 0.001 percent of the time they are right, they are not in a position to do anything about it. 

"Reporting it is of no use because the pilots will know of it just at the same moment the passengers do.

"A passenger who listens for noises, hoping to figure out if the plane is about to crash or not, is looking for trouble, obviously, and will find it – even when it doesn’t exist."