A320 / A321 Noise on Push Back
 

Just wondered if anyone can tell me what the wierd noise is that can be heard from under the floor of an A320 / A321 on push back. The best way of describing it is the loud noise of a car cranking on a flat battery! Same noise also heard after parking on stand. Is it parking brake? Its something unique to Airbus and not heard on a Boeing.

Noise of the PTU (POWER TRANSFER UNIT)

How many times has this question been asked?:ugh:

Out of interest which system(S) power the brakes on the scarebus?

Also does the activation of the PTU cause distracting messages on the ECAM or are they inhibited during start?

4,921

Green then Yellow

Not sure

Nothing untoward on ECAM.
HYD PTU shows on bottom right hand side of EWD during its self test on engine start. Would also be indicated on HYD page on SD if you were to select it.
Must be at least a week since this question was asked last:}

Mercy bucket monsieurs.

I shall remind myself of the search function. :}

HA! Told ya. More weird noises on an A320 then my dads 1979 Acco truck.

Well I think it sounds like an Alsation in the hold barking. I was wondering once whether to insist before pushback they dealt with the poor dog in distress in the rear hold! Could have been so embarrassing.

Thanks JEANS42TRF.

To the others who ridicule those of us less well informed - I never knew asking a simple techncial question out of curiosity having just been on 4 airbuses in 3 days would cause so much distress and inconvenience to you all. Apologies.

Don't GAW, ask the questions you want and forget about the other one.
Carry on with knowledge

Here to be corrected, but I think that the Ptu is inhibited during first engine start (so it will not be working) and during 2nd engine start is TESTED (that's when you hear it). So the ptu during the 1st engine start will not Sense any dp since it's inhibited.
[PTU pb sw
AUTO : The bidirectional power transfer unit is armed and both the yellow and the green electrohydraulic valves are open.
The power transfer unit runs automatically when the differential pressure between the green and yellow systems is more than 500 PSI.
Note : The PTU is inhibited during the first engine start and automatically tested during the second engine start. ] from the FCOM but

I don't really get when it kicks in, during the 2nd engine start or between the 2 start???
If it's inhibited it will not work, but if it's tested will it? or it's just a self test?
Anybody?


Note: You would also hear it if you did single engine taxing and when on the gate forgot to switch off the yellow elec pump.

Speevy

where is the PTU?( relatively to the plane)

close of the engine, or close of the Pack (behind the main landing gear).
any picture?

In the main wheel bay

Speevy, you're right....I should have read my FCOM before posting!:ok:

If I've said it once, I've said it 1000 times, we need a separate PPRune forum dedicated entirely to weird Airbus noises!:E

How about some weird Boeing noises?

Regards,

Old Smokey

Smokey,
Do you mean like the HMG on the B763???
cod

That's a good start cod liver oil, how about the ghostly howling banshee noises from the Air Driven Hydraulic pumps on the B777?

Regards,

Old Smokey

Just after the start of the second engine.

A320/321 Noise On Push Back
 

TASK 32-20-00-810-801- 01
Grinding Noise from the NLG during Taxiing or Towing (Trouble Shooting procedure Weight on Wheels)

NOTE:
The noise is because there is not sufficient lubrication in the shock absorber.This condition does not have an effect on safety.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.



If you mean grinding noise during towing(with tow bar) and taxiing above note answers your question and the TSM Task is given for rectification.