When I was a child, I lived with my family next to an airport,

We could tell without looking whether the plane passing overhead was an international or a local flight just by the noise it made.

You could hear them coming from far away and it often cut through conversations and rattled the windows of the house. It was deafening

The other day, on our way to an airport, my brother made a curious observation: “Have you noticed that planes are making less and less noise?” While he was saying this, a Qatar Arways international plane passed over us, of which we only noticed the shadow.

I started to get curious, do you know why?

NASA has developed changes in the fuselage and basic design components of the aircraft that have reduced the noise generated by these aircraft by 70%.

Fuselage and landing gear changes

A group of NASA researchers in the United States tested various components on a Gulfstream III aircraft, for example, by installing porous fairings on the landing gear to allow some air to pass through, as well as certain holes in the fuselage to mitigate noise. In aircraft, the fairing is an external covering whose main function is to reduce air resistance. It covers areas of the aircraft where potentially more drag can occur than in other areas.

In addition, changes in the space between the wing and the deployed flaps were evaluated, which made the tests conducted at the Armstrong Flight Research Center in California remarkably successful.

By recording the sound generated by a modified and unmodified aircraft with an array of 185 microphones, it was found that during approach and landing manoeuvres, for example, the deployment of the landing gear contributes significantly to the noise generated, reducing noise levels by up to 70% in some cases.

The noisiest and the quietest aircraft

Aircraft such as the B787 Dreamliner and A350, being more modern, are among the quietest.

In twin-aisle aircraft, sound is more dispersed than in single-aisle aircraft. For this reason, in addition to the efficiency of its engines, the A380 is considered to be the aircraft with the quietest cabin. And yet it is powered by four turbines.

Sound intensities during flight

In a flight there are different stages, each with a different sound intensity. The noisiest moment in a flight is the landing.

In the cabin, the quietest seats are those in front of the engines. This is logical: the sound generated by the turbines is expelled towards the rear.

By the same rule, the seats next to the window are noisier than those in the centre of the aircraft.

It is a physical principle: the sound intensity decreases inversely proportional to the distance from the source.

This is why first, business and premium economy class are located at the front of the aircraft, while the rest of the passengers flying from the wings to the tail are more noise bombarded.

If a passenger wants to sleep soundly and is a light sleeper, they should travel in a seat in the middle row (or along the aisle, if it is a narrow-body aircraft), even if this means sacrificing comfort or a view of the scenery.

But the biggest noise is not the engines, the biggest noise is the announcements coming out of the loudspeakers, don’t you think?