747400sp
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Is This Noise Normal On A330s @ Take Off?

Thu Dec 08, 2011 6:41 pm

I was watching this video of an US A330 taking off, and I wonder if this loud noise is normal on A330s when they take off?



Here is the link


http://www.youtube.com/watch?v=-GOWerl4pMU
 
Chamonix
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RE: Is This Noise Normal On A330s @ Take Off?

Thu Dec 08, 2011 6:50 pm

You can hear it even louder and clearer here:
http://vimeo.com/8814427
 
Ychocky
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RE: Is This Noise Normal On A330s @ Take Off?

Thu Dec 08, 2011 7:38 pm

Interesting.

OT: anyone notice the Tu-154 parked to the west of the BA Cargo buildings? Looks like a Slovakian Gov.
 
mickey90
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RE: Is This Noise Normal On A330s @ Take Off?

Thu Dec 08, 2011 7:46 pm

I've heard this sound many times before and not just on the a330.

I'm not 100% sure, but I believe you hear this sound when the pilots are using full thrust.
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Starlionblue
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RE: Is This Noise Normal On A330s @ Take Off?

Thu Dec 08, 2011 11:30 pm

You mean the buzzsaw right? Completely normal. It's the sound of the fan blade tips going supersonic.

As mickey90 says it happens on lots of aircraft. It is just more pronounced on some, the DC-10 for example.
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shufflemoomin
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RE: Is This Noise Normal On A330s @ Take Off?

Fri Dec 09, 2011 12:00 am

Quoting Chamonix (Reply 1):

You can hear it even louder and clearer here:
http://vimeo.com/8814427

Really good video. (I had a chuckle to myself that they have a disclaimer saying they'll take legal action for any illegal use when they have music in the beginning that is a clear rip off of Mofo by U2  
 
XFSUgimpLB41X
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RE: Is This Noise Normal On A330s @ Take Off?

Fri Dec 09, 2011 2:42 am

That howling noise at rotation that is intermittent in the USair video is most certainly not the buzz saw from the fan blades.

Interesting noise... Perhaps something to do with the hydraulics?

Edit- I watched the Swiss video. The howling noise was not audible from that one.

[Edited 2011-12-08 19:25:23]
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tdscanuck
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RE: Is This Noise Normal On A330s @ Take Off?

Fri Dec 09, 2011 4:36 am

Quoting XFSUgimpLB41X (Reply 6):
That howling noise at rotation that is intermittent in the USair video is most certainly not the buzz saw from the fan blades.

Agreed. Although buzzsaw is audible on this video, it's not the intermittent noise that starts at rotation.

Quoting XFSUgimpLB41X (Reply 6):
Interesting noise... Perhaps something to do with the hydraulics?

It sounds very much like an electric hydraulic pump. Based an a review of the A330 hydraulics documentation, it could be the yellow system electric pump coming online as the airplane goes from ground to air mode. However, it keeps going a lot longer than I'd expect based on what appears to be the yellow system automatic pump logic.

It could also be a cavity resonance but it's so loud and prominent that I'm surprised they wouldn't have fixed it.

Tom.
 
planejamie
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RE: Is This Noise Normal On A330s @ Take Off?

Fri Dec 09, 2011 5:28 pm

I also notice a mistake, that's definitely a A330-200, the spool up sounds just like a RR Trent 700. However, that noise isn't from the engines, I can hear the buzz-saw engine sound before the noise starts, I reckon the hydraulics, but I'm no expert on that.
 
AA737-823
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RE: Is This Noise Normal On A330s @ Take Off?

Mon Dec 12, 2011 12:32 am

NO, that noise is NOT normal.
I'm not sure what it is... I'm not convinced that it's an electric hydraulic pump. None of my electric hydraulic pumps sound that wretched...

I find the video's original comments to be quite annoying... apparently, no one bothered to tell this kid that turbulence has little to do with airplanes and more to do with, oh, WIND... and that you can also install in seat power in 777s, not to mention nine in PTV's....
I would not call any particular line number that makes this noise a "win" as he does. I do like the A330, but this one, as an airline mech, would make me a little nervous. But then, as an airline mech, I'm typically a nervous flyer anyhow.

It actually COULD be a leaky window seal, which would explain why it began during takeoff roll (pressurize to 50 feet below field level) and ended as Delta-P increased... Just a theory though.
 
AA737-823
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RE: Is This Noise Normal On A330s @ Take Off?

Mon Dec 12, 2011 12:35 am

In addition, the video poster is actually completely wrong- he's jumping up and down about how he's on a 333, in spite of people telling him that it's a 332 with Rolls power... But I've now got proof! The ECU cooling air inlet is plainly visible in front of the engine strut, which is where it's located on a ROLLS engine. The Pratt that US uses to power their 333's doesn't have one.
So, he's on a 332 with a Roller. Someone should educate him, and also give him an internet tongue-lashign for being such a pratt himself.
 
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Starlionblue
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RE: Is This Noise Normal On A330s @ Take Off?

Mon Dec 12, 2011 1:02 am

Quoting AA737-823 (Reply 10):
In addition, the video poster is actually completely wrong- he's jumping up and down about how he's on a 333, in spite of people telling him that it's a 332 with Rolls power... But I've now got proof! The ECU cooling air inlet is plainly visible in front of the engine strut, which is where it's located on a ROLLS engine. The Pratt that US uses to power their 333's doesn't have one.
So, he's on a 332 with a Roller. Someone should educate him, and also give him an internet tongue-lashign for being such a pratt himself.

Nothing good can come of getting involved in YouTube comments.   
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Speedbird741
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RE: Is This Noise Normal On A330s @ Take Off?

Tue Dec 13, 2011 11:43 am

Quoting AA737-823 (Reply 9):
NO, that noise is NOT normal.

As a regular flier on the A343, I actually hear this exact sound quite often as well. Curiously enough, I've heard it during takeoff and landing (it becomes very pronounced during flare). I have always been inclined to believe that it is the yellow electric pump, but since I heard the sound increase so much during flare I thought it might have something to do with air flowing irregularly through the slats. Just basic speculation on my behalf of course, but I would like to hear your thoughts on that. I also have a video of the occurence should you be curious enough to watch it. Here is a youtube video of the same sound on a Cathay A343 starting at 6:18.

http://www.youtube.com/watch?v=Uj3Yb...648F2F6&index=5&feature=plpp_video

Speedbird741
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EMBQA
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RE: Is This Noise Normal On A330s @ Take Off?

Wed Dec 14, 2011 3:30 am

This kind of question gets asked all the time on A.net about different aircraft and ...'what sound is this.. is it normal'.....So much of it is dependent on many-many different veriables. Quality of the microphone, quality of the source, location recorded in the aircraft, weather conditions, type of engine even down to the airlines choice in insulation. If you were seated in seat 15A it would sound different to someone seated in 18C. The sound envelope changes as you sit in different places around the cabin.

[Edited 2011-12-13 19:32:09]
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Airbus_A340
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RE: Is This Noise Normal On A330s @ Take Off?

Wed Dec 14, 2011 11:16 am

Quoting XFSUgimpLB41X (Reply 6):
Interesting noise... Perhaps something to do with the hydraulics?
Quoting tdscanuck (Reply 7):
It sounds very much like an electric hydraulic pump. Based an a review of the A330 hydraulics documentation, it could be the yellow system electric pump coming online as the airplane goes from ground to air mode.

Just to clarify, none of the electric hydraulic pumps are operating during this phase of flight under normal circumstances for A330/A340.
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mafi29
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RE: Is This Noise Normal On A330s @ Take Off?

Wed Dec 14, 2011 1:19 pm

Quoting AA737-823 (Reply 9):
pressurize to 50 feet below field level


Just out of curiosity: Why is the cabin pressurized to 50 ft below field level at take off?

I know it is off topic, so please forgive me.

[Edited 2011-12-14 05:22:18]
 
tdscanuck
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RE: Is This Noise Normal On A330s @ Take Off?

Wed Dec 14, 2011 2:15 pm

Quoting Airbus_A340 (Reply 14):
Just to clarify, none of the electric hydraulic pumps are operating during this phase of flight under normal circumstances for A330/A340.

I misread this manual: http://www.smartcockpit.com/pdf/plane/airbus/A330/systems/0012/

The auto yellow pump would only come on if engine 2 failed, correct?

Tom.
 
je89_w
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RE: Is This Noise Normal On A330s @ Take Off?

Wed Dec 14, 2011 3:24 pm

Interesting sound, something I've never heard before either. And yes those are Rolls Royce Trent 700s, so without a doubt it's a US Airways A332 in spite of what the Youtube user said.

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