A320 sudden noise increase at 10000 feet

[JammedStab]

I have noticed this quite a few times on descent at an altitude that seemed to be at around 10000 feet. I figured that it was landing lights being extended(I suppose that comes from older aircraft types).

But a recent article I read about Gatwick noise charges may have answered the question. Unfortunately, no link available.

The article says that Gatwick is charging A320 operators extra if they have not installed a mod to cut down on the noise(by up to 11 db). I suppose, it is audible on the ground as well.

Apparently, the noise comes from the fuel over-pressure protector cavity with the noise typically being emitted at 27-6.5 nm from landing. Is this the noise I hear in the cabin on descent?

[EGPFlyer]

I agree that it's probably the lights being extended or the speed brakes, both of which will be heard in the cabin due to the extra drag. The deflectors for the fuel vents reduce a noise that you would only hear on the ground.

[Uplinker]

I don't fly Boeing, but A320 family speed brakes sometimes emit a breath-like tone, similar to blowing across the top of a bottle, starting with a high frequency and reducing in pitch the further out the brakes are set.

When the brakes are stowed, the tone goes from low to high pitch.

A bit like the flaps on the BAe146 and for similar reasons; resonance of air in the gap between the moving surface and the wing - the size of the gap determining the frequency.

The A320 family landing lights add a bit of rumble and vibration to the noise inside the aircraft when they are deployed.

[EmDeer]

A quick Google search showed me this:


An even quieter approach: Airbus introduces air flow deflectors on the A320 Family | Airbus Press release (http://www.airbus.com/newsevents/news-events-single/detail/an-even-quieter-approach-airbus-introduces-air-flow-deflectors-on-the-a320-family/)

Major European Airbus operators take steps to avoid A320 whistle noise nuisance on GreenAir Online (http://www.greenaironline.com/news.php?viewStory=2116)

a320 Whine (http://a320whine.com/)

[B2N2]

Does the pressurization logic have anything to do with it?

[JammedStab]

It is definitely not speed brake deployment that I have been hearing but just to confirm then...there are lights that extend from the aircraft.

[Denti]

Yes, right out of the underside of the fuselage. And in our outfit they have to be on below FL100, therefore around that altitude during descend they get extended and turned on.

[Lookleft]

And can anyone explain why Airbus decided to put the landing lights there and not in the wing body fairing?

[applecrumble]

Because that would be too similar to a Boeing :}

[Fursty Ferret]

And can anyone explain why Airbus decided to put the landing lights there and not in the wing body fairing?


Miniature speedbrakes. Landing light extension is part of my descent planning on a CDA... ;-)

[Amadis of Gaul]

Polish speedbrakes. Or Italian speedbrakes.

[TURIN]

A320 landing lights are in the wing root. Not the fuselage.

[EEngr]

Polish speedbrakes. Or Italian speedbrakes.

Are you certain the Germans didn't have some input into this design?

https://petrollovers.files.wordpress.com/2013/03/porsche928lightsup1327116809.jpg

[Intruder]

Cessna 310. Theirs were under the wing, too.

[EEngr]

Cessna 310. Theirs were under the wing, too.

That's understandable, given the dimensions of a classic incandescent landing light and the limited height of a wing root fairing where a fixed light could be mounted.

What with the increasing performance of LED lighting and the flexibility of design of LED arrays, future aircraft designs may incorporate fixed lighting in locations that won't accommodate big, round lamps.

[Intruder]

...but they may have to give way to the distributed radar arrays. ;)

[RVF750]

Like the 737 you mean? Current ones lose not only the extending landing lights but the taxi light on the nose is gone too. Those LEDs are VERY good indeed.....

[FlightDetent]

A320 landing lights are in the wing root. Not the fuselage. Underside of the wing.