HorizonGirl
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A320 PTU Question

Wed Mar 30, 2005 4:03 pm

Hello everyone!

I am sorry if this topic has been previously discussed,
but I did a forum search and nothing turned up. I tried asking this
in an other thread, but it was soon after locked.
My question is why dose the A320 PTU "Bark?"
I know how it works, what it is, and that some people get
quite nervous when they hear it.
But what is it exactly that makes it make those impossible to ignore barks?  Yeah sure
Thank you for any help that you may be able to provide.

Devon
Flying high on the Wings of the Great Northwest!
 
gocaps16
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RE: A320 PTU Question

Wed Mar 30, 2005 4:18 pm

A PTU is like a dog...for some reason it just barks  Smile

Kevin
 
HorizonGirl
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RE: A320 PTU Question

Thu Mar 31, 2005 12:55 pm

LOL, They should recognize the PTU as an official breed!


Devon
Flying high on the Wings of the Great Northwest!
 
cactusTECH
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RE: A320 PTU Question

Wed Apr 13, 2005 10:23 pm

The PTU is mechanical pump that links the yellow and the green hydraulic systems. It is energized when either system has been turned off( ex: one engine off) it produces a loud high frequency noise when it turns and produces 3000 psi hydraulic pressure for oppsosite system.
 
troubleshooter
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RE: A320 PTU Question

Thu Apr 14, 2005 1:41 pm

I think, the noise is produced by the fast moving (rotating) mechanical components inside the PTU. This leads to high frequency vibrations which are translated by the attached plumbing and PTU mounts.
All PTUs I know can be recognized by a loud "barking" sound. So I assume the noise is related to the PTU design and not only a A320 specific noise.
This job sucks!!! I love this job!!!
 
Klaus
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RE: A320 PTU Question

Thu Apr 14, 2005 7:52 pm

One forum member has once explained that Airbus explicitly wanted to have the PTU sound clearly audible to make troubleshooting on the ground easier. I don´t know if that´s exactly correct, but it might be an explanation. Newer versions are reported to be somewhat less noticeable (also from earlier threads).
 
fadec
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RE: A320 PTU Question

Thu Apr 14, 2005 8:03 pm

The reason it "barks" is because it switches on and off so quickly. As pressure drops it comes on just long enough to build the pressure back to 3000 psi. Once that is done it shuts off until the pressure drops again... in about 5-15 second intervals normally, depending on how good the pressure bleed down rate is on that particular aircraft.

If you lower the flaps for instance the barking will stop and you will hear the pump run continuously (which is also quite loud) until the pressure is built back up after system demand has stopped.

I believe the A320/319 is the only aircraft you can hear the PTU so distinctly during normal operations. The 757/767 ETOPS for instance, it is heard only with a system failure. I've personally only heard it during maint. test's. Most non-ETOPS aircraft don't even have a PTU.
 
UAL Bagsmasher
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RE: A320 PTU Question

Thu Apr 14, 2005 8:06 pm

The BAE-146 also "barks" quite loud, at least in the hangar.
 
SlamClick
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RE: A320 PTU Question

Thu Apr 14, 2005 11:09 pm

Quoting UAL Bagsmasher (Reply 7):
The BAE-146 also "barks" quite loud, at least in the hangar.

Ahhh, but that is because the BAe-146 is a dog.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
MD11Engineer
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RE: A320 PTU Question

Fri Apr 15, 2005 4:31 am

All hydraulic pumps make noise, on engine driven pumps it is usually drowned by the engine noise, but did anybody in here ever stick his head into the "B" system compartment of a 727? You´ll need ear protection because of the racket the two electric driven pumps make. The same applies to the R/H wheel well of a MD-11.

Jan
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HorizonGirl
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RE: A320 PTU Question

Fri Apr 15, 2005 5:26 am

Thank you everyone so much.
Figured it had to do with the pressure but wasn't 100% sure.
Now that I know for sure I can go back to talking at my
friends about this.
Devon
Flying high on the Wings of the Great Northwest!
 
UAL Bagsmasher
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RE: A320 PTU Question

Fri Apr 15, 2005 10:08 am

Slamclick, we actually call it the "Pig". But either way, it's an animal that will turn around and bite you in the a** as soon as you let your guard down. (From an A&P's view at least Wink)
 
gocaps16
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RE: A320 PTU Question

Fri Apr 15, 2005 11:30 am

LOL, are your friends interested in the "barking" sound of the PTU?

Kevin
 
LHB727230Adv
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RE: A320 PTU Question

Fri Apr 15, 2005 2:37 pm

I know this is a stupid question coming from me, but what exactly is a PTU and what is it used for?

Cheers,
Alex  bigthumbsup 
 
NKP S2
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RE: A320 PTU Question

Fri Apr 15, 2005 9:08 pm

Quoting LHB727230Adv (Reply 13):
I know this is a stupid question coming from me, but what exactly is a PTU and what is it used for?

Stupid? No. Lazy, maybe. Read the 3rd reply. See also other recent thread: http://www.airliners.net/discussions/tech_ops/read.main/93654/

Some good info amongst all the "fan" fluff. That and multitudinous other posts in multiple other threads discussing same.
 
LHB727230Adv
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RE: A320 PTU Question

Fri Apr 15, 2005 10:29 pm

Thanks, NKP S2, I must have missed reply 3.  banghead 
Wierd, I never noticed the A320 barked, I've flown on it dozens of times and never heard a barking sound.

Cheers,
Alex  bigthumbsup 
 
HorizonGirl
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RE: A320 PTU Question

Sat Apr 16, 2005 11:11 am

You would have to be sitting around the wing area in
order to hear it.

Devon
Flying high on the Wings of the Great Northwest!
 
LHB727230Adv
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RE: A320 PTU Question

Sat Apr 16, 2005 4:18 pm

Quoting HorizonGirl (Reply 16):
You would have to be sitting around the wing area in
order to hear it.

Thanks, I'll keep that in mind for next time I fly the A320

Cheers,
Alex  bigthumbsup 
 
HorizonGirl
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RE: A320 PTU Question

Mon Apr 18, 2005 7:47 am

Quoting GOCAPS16 (Reply 12):
LOL, are your friends interested in the "barking" sound of the PTU?

I teach a fear of flying class, but aside from that,
I would say not. laughing 


Devon
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HAWK21M
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RE: A320 PTU Question

Mon Apr 18, 2005 1:14 pm

Any Audio of this "Barking" sound.On the A320 that is  Smile
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
F-WWAI
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RE: A320 PTU Question

Tue Apr 26, 2005 6:21 am

the PTU is there to transfer hydraulic power from Green to Yellow or from Yellow to Green hydraulic system, but without exchange of hydraulic fluid.
It's a motor/pump power reversal configuration.
While normal system pressure is 3000 psi, the Power Transfer Unit cuts in when the receiving system pressure falls below 2500 psi. If there is high consumption of hydraulic power on the receiving system, then the PTU operation is continuous.
If there is only system leakage flow, then the PTU barks coming ON and OFF. The ops is normally inhibited on ground when the parking brake is set for standard engine starting at departure. But for any single engine pushback or taxi ops the PTU will wake up.
have fun,
watch airbus,
fw
 
HorizonGirl
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RE: A320 PTU Question

Wed May 18, 2005 9:41 am

Thank you so much!!!!!!!!!!

I started this thread and brought up all the old PTU threads
for a school project I was doing on the A320.
I did very well, and I couldn't have done it with out
you all. Special thanks to everyone who gave me extra material and info.  bigthumbsup 
Once again, thank you.

Devon
Flying high on the Wings of the Great Northwest!
 
VC-10
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RE: A320 PTU Question

Wed May 18, 2005 12:54 pm

Quoting Klaus (Reply 5):
One forum member has once explained that Airbus explicitly wanted to have the PTU sound clearly audible to make troubleshooting on the ground easier. I don´t know if that´s exactly correct, but it might be an explanation. Newer versions are reported to be somewhat less noticeable (also from earlier threads).

It's a novel idea. I would have thought a look at the hyd pressure being generated by the PTU on ECAM would have been a more positive way of trouble shooting  Smile

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