kaype, it's actually called an airflon bearing.

The noise is because there is not sufficient lubrication in the shock absorber:-The shock absorber is almost full of oil.

If it is not possible to do the lubrication procedure immediately (because there is not sufficient time or equipment),do it at the first opportunity.

How much equipment does it take to squirt about a half to a litre of mil-prf-5606 into a hole at the rear of the NLG.

A320/321 Noise On Pushback
 

All that glitters Thanks for ur info on Airflon coated Ring :)

This note I had attached is taken from A320 Trouble Shooting Manual.
In simple English if the transit time is short U can do the lubrication later,being an Engineer myself if I have limited time i would rather diferr it to be done during night stop.So safe for dispatch nd no delays.

On some our new A320's the barking PTU is less audiable and not so obvious.

Noise on push back but during flight
 

Hello,

I am just wondering about a nosie on a recent A320 flight.

I am used to the PTU noise (many A320 flights..) at startup on the push back etc...but, I heard this noise for over a minute several times yesterday on my flight back from Cancun. It was over a minute on the ground. Then heard it for short spurts during flight, then again for almost two minutes mid flight and then it was in spurts again on appraoch and then ran again fro 1-2 minutes after we got to the gate.

I have never heard so much from noise and wonder if we were in any danger or if something was not working, leaking or whatever?

I appreciate any responses as I have many more A320 flight scoming up.

Thanks
DGD

noise mid flight
 

just to clarify my question - does the ptu normally run for minutes during flight whike at 34000 feet?

thanks
DGD

Hi DGD,

No it doesn't. It is probably a spurious PTU activation when it's not supposed to. Had it a few times on some old A321s.

It's been awhile,but I want to say that I've heard a sound similar to the A32X PTU activation noise during push back on board the B717 too. Anyone else ever heard it on this type? I know that I've also heard it on Airbus narrowbodies.

Cheers GP9

Here is a video of the ptu:

YouTube - Airbus A320 PTU or...the barking dog!

Great!:ok:

Question from ancient engineer (AFCS for the pointy one).

What's this PTU, what does it do, and why does it bark when it operates (yes, I've looked at/listened to the U-Tube videos) ?

And no, I don't have any A-320 manuals I can refer to....

CJ

Power Transfer Unit. Transfers hydraulic power from green system to yellow system (or vice versa) if a pump (or an engine) fails.