KELPkid
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A320: Dental Drill Sounds?

Wed Jul 19, 2006 2:27 am

My wife and I were on a UA A320 flight at DEN yesterday, and on taxi-out (a couple of miles at DEN  Wink ), the aircraft was making sounds very similar to the pneumatic drill at the dentist's office (sorry, this is the best description I can come up with). Just curious what the sound might be. They were taxiing on one engine, so I'm wondering if this is related to special hardware to cope with one hydraulic system being out, etc. The sounds went away as soon as the second engine was started.

Thanks,

Brent
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SlamClick
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 2:50 am

Not again!

Forum search: "Airbus" "noises" "sounds""barking dogs"

The explanation of those noises should be part of the Tech/Ops page header.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
n8076u
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 3:26 am

Quoting SlamClick (Reply 1):
Not again!

This does seem to come up fairly often.  Wink

What you heard is the PTU, power transfer unit, which is part of the hydraulic system.

Chris
Don't blame me, I don't work here...
 
SlamClick
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 3:28 am

Here's one: RE: A320/A319 "barking" After Shutdown (by SlamClick Apr 12 2005 in Tech Ops)#ID115403

It is the hydraulic PTU.
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SlamClick
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 8:57 am

Attn: Threadstarter.

Acknowledging that you got the information you wanted keeps you on the list of people who get their questions answered.


Failing to do so does not, on the other hand, give you immunity from smartass remarks like

Quoting SlamClick (Reply 1):
Not again!

Forum search:

and

Quoting N8076U (Reply 2):
This does seem to come up fairly often.

or

Quoting NKP S2 (Reply 4):
Surely a use of a search function is within your purview then.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
KELPkid
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 9:39 am

Quoting SlamClick (Reply 5):
Acknowledging that you got the information you wanted keeps you on the list of people who get their questions answered.


Message received.

Yes, I got the info that I was after, thanks  Smile

Quoting SlamClick (Reply 5):
or

Quoting NKP S2 (Reply 4):
Surely a use of a search function is within your purview then.


I did suggest this smartypants response for deletion...and funny, a thread search on A320 and "dental drill" yielded no answers. Don't even try A320 and "noise", you'll be wading through the hits for hours!  Wink
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hangarrat
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 10:40 am

Interestingly, I'd flown on A320 series planes a dozen or so times before I noticed the noise. Thankfully I'd read at least four dozen threads about the barking noises by that point, so when I heard them I was able to tell my fellow pax exactly what it was.

I agree, it sounds like a robotic St. Bernard in the cargo hold.
Spell check is a false dog
 
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HAWK21M
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 4:49 pm

Power Transfer Unit.
Do a Search...You'll be surprised on the Number of Threads.  Smile
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
SlamClick
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 10:55 pm

Quoting KELPkid (Reply 5):
thread search

Well, to all the people who are spring-loaded to the 'do a search' response, let me suggest that you try the search.

It took me nearly an hour to come up with the thread I linked to in post #3. All us long-time readers here know that question comes up about once every six months or so, and that a couple of the early threads on it have maybe a hundred replies. So I tried a search with...

"Airbus" and "sound"
"Airbus" and "noise"
"Airbus" and "drilling"
"Airbus" and "barking"
"A-320" and "sound"
"A-320" and "noise"
"A-320" and "drilling"
"A-320" and "barking"

...and got nothing. Eventually I dredged it up by going through all my posts in old Tech/Ops threads. So maybe the search function ain't all that wonderful and maybe its okay if this one pops up from time to time.

I still think it should be part of the page header.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
David L
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RE: A320: Dental Drill Sounds?

Wed Jul 19, 2006 11:57 pm

Quoting HangarRat (Reply 6):
Interestingly, I'd flown on A320 series planes a dozen or so times before I noticed the noise.

Same here, I'm embarrassed to say. I don't know how I could have missed it! I think I just assumed it was the stabiliser being trimmed, or something similar, and tuned it out.
 
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Starlionblue
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 3:10 am

Quoting SlamClick (Reply 8):
I still think it should be part of the page header.

Definitely. Soon to be joined by "The 380 only has 2 reversers? Surely this will cause it to break up in mid-air and land on John Leahy!"
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
KELPkid
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 3:38 am

Quoting Starlionblue (Reply 10):
Definitely. Soon to be joined by "The 380 only has 2 reversers? Surely this will cause it to break up in mid-air and land on John Leahy!"

And don't you forget, those are trust reversers, too  Wink
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AC773
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 9:31 am

I also need info on a strange A320 noise, but what's been described above doesn't seem to match it. What I hear happens between boarding and pushback. It's a very loud, high-pitched whine that goes on for a good few minutes. It stops, and then starts again for another couple of minutes. What on earth is this?

Also, did Airbus hire GKirk to install their overhead bins? Every 320 family aircraft I've been on has heavy "bin rattle" on taxi and landing. I've never experienced anything like this on a Boeing, so I'm assuming it's just the "Frenchness" showing through.  Wink

-AC773
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n8076u
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 10:29 am

Quoting AC773 (Reply 12):
What I hear happens between boarding and pushback. It's a very loud, high-pitched whine that goes on for a good few minutes.

Could be the hydraulic pumps you are hearing, as those put out a high-pitched whine.

Quoting AC773 (Reply 12):
Every 320 family aircraft I've been on has heavy "bin rattle" on taxi and landing. I've never experienced anything like this on a Boeing,



The A320 fuselage flexes quite a bit more than a similarly sized Boeing, like the 737. That is why the stowbins tend to rattle, creak and groan a bit more. It is also fun to watch the stowbins undulate if you are sitting all the way in the back through turbulence.

Chris
Don't blame me, I don't work here...
 
SlamClick
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 11:16 am

Quoting N8076U (Reply 13):
Could be the hydraulic pumps you are hearing, as those put out a high-pitched whine.

Good illustration of the wisdom of NEVER going back to change an answer unless you uncover hard data that contradicts your first guess.

The first answer that occurs to you does so for a reason.
The second is just self-doubt.

It is the PTU.
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n8076u
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 4:54 pm

Quoting SlamClick (Reply 14):
Good illustration of the wisdom of NEVER going back to change an answer unless you uncover hard data that contradicts your first guess.

Different answer for a different question. If you read into what "AC773" said:

Quoting AC773 (Reply 12):
but what's been described above doesn't seem to match it. What I hear happens between boarding and pushback. It's a very loud, high-pitched whine that goes on for a good few minutes. It stops, and then starts again for another couple of minutes.

"AC773" seemed to be asking about a different sound, rather than than the infamous "barking dog", since I wouldn't characterize the PTU sound as a high-pitched whine, but rather a low pitched growl. But the electric hydraulic pumps sure do fit that profile, as those pumps make a very high pitched whine that does not sound like a barking dog in any way.

The timing also makes me think he's talking about the electric hydraulic pumps. The cargo doors are hydraulically powered on the A320. During/after boarding but before pushback, the yellow system hydraulics would come on should someone close a cargo door, and will continue to run for a bit after the cargo door open/close switch is released. This sound happening twice, once for each cargo door before pushback makes this explanation seem more correct than the default PTU answer. And he did not state that it also happened during pushback, taxi and takeoff, like the PTU sound would have.

Chris

[Edited 2006-07-20 10:09:16]
Don't blame me, I don't work here...
 
bri2k1
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 8:34 pm

Quoting SlamClick (Reply 8):
It took me nearly an hour to come up with the thread I linked to in post #3

 Wow! that's dedication!
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ilikeyyc
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 9:48 pm

Quoting SlamClick (Reply 8):
...and got nothing. Eventually I dredged it up by going through all my posts in old Tech/Ops threads. So maybe the search function ain't all that wonderful and maybe its okay if this one pops up from time to time.

This is directed at everyone who uses the "Search Topic" feature:

Say you are searching for "A320 Noise". You must put the stars (*) around your search, or else the only threads that will be retuned are the ones with a title of "A320 Noise".

Examples (click on the link to see the search results):

A search for A320 Noise
vs.
A search for *A320*Noise*

*a320*barking*

*a320*sound*

see also Is Anything Being Done To Improve The Search? (by Corey07850 Jul 16 2006 in Site Related)
Fighting Absurdity with Absurdity!
 
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Starlionblue
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RE: A320: Dental Drill Sounds?

Thu Jul 20, 2006 11:17 pm

Good tips Ilikeyyc! Thanks.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
KELPkid
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 1:58 am

Quoting Starlionblue (Reply 18):
Good tips Ilikeyyc! Thanks.

Definitely.

[human factors mode]The user should be shielded from having to use Unix shell wildcards in a search![/human factors mode]

The techie in me knows about Unix shell wildcards, and their application...however, the 1 year of college studies in human factors psychology tells me the user interface on the search should shield one from this.

Sorry, end of off-topic rant. I realize tech-ops isn't the place for this...

Brent
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ilikeyyc
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 2:08 am

You're welcome!

I got frustrated with it one day because I too was trying to search for something I knew existed, but the search engine would not find it. On a hunch I put the stars around it and it worked.

Quoting KELPkid (Reply 19):
[human factors mode]The user should be shielded from having to use Unix shell wildcards in a search![/human factors mode]

It is backwards. You are right, the user shouldn't have to put wild cards in the search, but if the user wants to return an exact phrase, then one should use " or whatever it is that they use for phrase matching. (I'm not a computer guy- I know how to turn it on and find the internet- that's it)
Fighting Absurdity with Absurdity!
 
bri2k1
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 4:40 am

It seems a little silly to complain about something that's clearly posted right on the search page:

Quoting Search Page (Emphasis Added):
  • Use "Seach Topic" to search through the topics of forum posts. Note that you can use * to match any character.
  • Use "Seach for username" to search through the usernames of those who posted in the forum. Note that you can use * to match any character.
  • Use "Search Topic & Body" to search for words that exist in either the topic or the message body. Type in more than one word in the "Search Topic & Body" field and the engine will find entries containing WORD1 AND WORD2. For instance, the keywords Boeing 747 will match all entries containing Boeing AND 747. If you wish to find entries containing an exact phrase, include the phrase in double quotes. A search for "Boeing 747" will match all entries containing the exact phrase Boeing 747. This field only finds full words and you can not use the wildcard character (*). For instance, a search for Boe* does not match Boeing.
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Starlionblue
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 7:07 am

Quoting KELPkid (Reply 19):

[human factors mode]The user should be shielded from having to use Unix shell wildcards in a search![/human factors mode]

The techie in me knows about Unix shell wildcards, and their application...however, the 1 year of college studies in human factors psychology tells me the user interface on the search should shield one from this.

I also knew about Unix wildcards, but with Google not requiring them, I was out of practice and imagination  Wink
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
RyDawg82
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 8:33 am

Alright...I have an airbus noise question....Although I don't know if anyone is still looking at this thread for reasons other than how to use the search function Big grin

I have noticed that Airbus 320 (The entire family) have a unique howl on approach that can be heard as the bird passes overhead. I can best describe the sound as that a C-5 makes taking off, but from a far distance. I am not talking about the distinct sounds this aircraft makes on takeoff, again it's just as the aircraft is flying overhead on approach, say 2500-3000 ft AGL...Can anyone explain to me what causes this?

Thanks,
Ryan
 
KELPkid
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 8:50 am

Quoting RyDawg82 (Reply 23):
Alright...I have an airbus noise question....Although I don't know if anyone is still looking at this thread for reasons other than how to use the search function Big grin

I have noticed that Airbus 320 (The entire family) have a unique howl on approach that can be heard as the bird passes overhead. I can best describe the sound as that a C-5 makes taking off, but from a far distance. I am not talking about the distinct sounds this aircraft makes on takeoff, again it's just as the aircraft is flying overhead on approach, say 2500-3000 ft AGL...Can anyone explain to me what causes this?

Which Engines (CFM or IAE)? Who's the Airbus operator? It makes a difference, if you're talking about the infamous A320 "buzzsaw" sound, I've only ever heard that on IAE V2500-powered airbii  Wink
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RyDawg82
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 9:15 am

Hey....Again this isn't the buzzsaw sound heard when the engine are at higher power....This is simply a howling sound made by the aircraft, or perhaps the airflow through the engines at idle....

The particular A/C was a US/HP 319....However I recall being in downtown Seattle and hearing every 319/320 passing over making the sound....Both CFM and IAE....

Ryan
 
KELPkid
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RE: A320: Dental Drill Sounds?

Fri Jul 21, 2006 9:28 am

Quoting RyDawg82 (Reply 25):
The particular A/C was a US/HP 319....However I recall being in downtown Seattle and hearing every 319/320 passing over making the sound....Both CFM and IAE....

Must've been the sound of the stealth guided missile being fired from BFI, PAE, or Renton by disgruntled Boeing employees  Wink Fortunately, they miss every time...
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HAWK21M
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RE: A320: Dental Drill Sounds?

Sat Jul 22, 2006 1:02 am

Quoting KELPkid (Reply 26):
Fortunately, they miss every time...

Are they using Airbus Equipment  Smile
Amazing Aircraft the A320.In fact the IC A320s APU sounds louder than the V2500 Engines.
regds
MEL
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arluna
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RE: A320: Dental Drill Sounds?

Sat Jul 22, 2006 1:10 am

I have heard this sound and it seems to me that Airbus should have found a way to isolate the PTU from the A/C structure so that the noise wouldn't be quite so intrusive. There were some first time flyers on a recent flight I was on and they were quite alarmed when the thing started whining. It was really loud in the area between the wings.

Arluna
 
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scbriml
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RE: A320: Dental Drill Sounds?

Sat Jul 22, 2006 2:15 am

Quoting AC773 (Reply 12):
I also need info on a strange A320 noise, but what's been described above doesn't seem to match it. What I hear happens between boarding and pushback. It's a very loud, high-pitched whine that goes on for a good few minutes. It stops, and then starts again for another couple of minutes. What on earth is this?

Isn't that the FAs doing the safetly briefing? duck 
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KELPkid
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RE: A320: Dental Drill Sounds?

Sat Jul 22, 2006 2:27 am

Quoting Scbriml (Reply 29):
Isn't that the FAs doing the safetly briefing? duck

I Wish, most US A320 operators now use the flip-down LCD screens and a canned video for the safety briefing  Sad Hey, gotta dig that chick on HP Big grin (I wonder if HP and US now use the same safety briefing...two days after the merger it was still the HP safety breifing!).
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bri2k1
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RE: A320: Dental Drill Sounds?

Sat Jul 22, 2006 7:32 am

The first chick who speaks on the Ted video is cute too, but she's FAR too excited to be giving a safety briefing. The video actors have obviously never even heard a real safety briefing, 'cause they're not convincing at all...
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AC773
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RE: A320: Dental Drill Sounds?

Sat Jul 22, 2006 7:40 am

Quoting KELPkid (Reply 30):



Quoting KELPkid (Reply 30):
(I wonder if HP and US now use the same safety briefing...two days after the merger it was still the HP safety breifing!).

No, these days they've got the same video for both HP/US. No hot chicks, but there is a beautiful fly-by shot with an A320 in new colors.  drool 
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