A330 drivers?

[knobbygb]

I know this is really boring, but I'm working nights and have nothing better to do so here goes...

Can any A330 (or 340) people tell what the loud banging/clanking noises are coming from the area of the main landing gear during taxi. I've heared this a few times now on different aircraft (SN and US) - but only on A330's. The obvious answer is that it's somthing to do with how the brakes work, but somthing more technical that that would be appreciated. And why just the ~A330? Are the brakes very different to other wide-body types? I've been on A340's and not heard the noise.

On a recent flight, several passangers sat in the center of the main cabin heard the noise and were actually concerned enough to mention it to the crew. (We'd just had a 1 hour tech. delay and this was on September 16th, so I can see why they were a bit jittery).

[ZK-NSJ]

i have heard similar noises on the A310

[ZK-NSJ]

only start worrying when you hear the noises in the air

[expedite_climb]

Taxi lights ??

[???pax]

I've heard similar noises on the 319. I thought it was flaps for take off being set but I was wrong.

[Busta Level]

It's the brakes. Pretty common on all the A319/320/321/330 and 340 aircraft. What you hear is a 'klunk' as the brakes are applied. We can hear it up the front as well. I believe that it happens as the brake liners (pads) take up the 'slack'. It is worse on some aircraft than others, and non-existent on some!

I guess it depends on how the brakes are fitted, because it has disappeared on some aircraft after a wheel unit/brake change, and appeared on others.

On another note, it is always worth listening out for the hydraulic PTU transferring power during the first engine start on the 320. Makes a loud whirr that often catches people unaware, especially if you are sitting between the wings. I've seen one pax (who was dozing quietly in his seat at the time) leap into the air like a startled rabbit <img src="wink.gif" border="0">

[Wycombe]

Yep, I heard some pretty loud clanking on a JMC 320 during taxi a few months back....did wonder what it was.

Also have heard some funny, sort of twanging-type noises on 747's during taxi round sharp corners...I'm guessing this is the MLG steering??

[knobbygb]

Thanks BustaLevel - thought it was the brakes but nice to hear it from the horses mouth. Mind you, seems a pretty odd way to go about things - some aircraft do it (sometimes) and some don't - how do you know if you've got a real problem? If my Pa28 starts 'clanging' 'twanging' and 'clunking' (nice technical descriptions eh?) like that I'll start to worry but I guess things are a bit more complicated for you guys.

[Hamrah]

The PTU on the A320 is also quite noisy whenit is first powered up before engine start...sounds like some crashing a gearbox. Bit disturbing for passsengers in Row 12

H