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Loud Engine Noise On CX 744

Fri Oct 10, 2008 6:29 pm

Hello All,
I just flew back from HKG yesterday on CX 870 Tail Number B-HUG.
I got a whole row 63 ABC to myself in the rear end of Economy Cabin. As soon as the aircraft went airborne, the engines were so loud that we could not hear any PA announcements or the crew requests during beverage and meal services. It was very hard to even hear the inflight entertainment system throught the flight. I could bearly sleep as the engines were buzzing all night. I have flown many other 744's and have never experienced this. On the outbound flight on CX 744, I was seated in row 53K (whole row) tail number B-HOZ where similar problem was faced. What would be the reason for the engines to be super loud? Is it because the aircrafts would have been really old? Can thoughts?
Rgds,
744
 
kappel
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RE: Loud Engine Noise On CX 744

Fri Oct 10, 2008 7:46 pm

It's because you were sitting in the back, even the a340 is loud in the back. If you sit above or in front of the wings the next time, you'll notice a big difference. It has nothing to do with the age of the aircraft.
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spacecadet
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RE: Loud Engine Noise On CX 744

Fri Oct 10, 2008 8:19 pm



Quoting Kappel (Reply 1):
It has nothing to do with the age of the aircraft.

It might have something to do with it, but maybe not in the way he means.

In a lot of older aircraft, various interior panels are just a little bit loose, and they will vibrate during cruise if the frequency of the sound from the engines matches their harmonics. The vibration can often be more violent than you'd expect - I've found panels that were vibrating with my hand, and they were vibrating so hard that I couldn't stop them by pressing down.

In an older plane (or at least a plane with an older interior), you can have a dozen panels vibrating in various parts of the cabin and giving off noise, and it can sound like a pretty terrible racket. It's especially true in the back of the plane where it's louder anyway and you can't easily tell that the sound isn't all coming from outside.

Also, that plane does have RR engines - I'm not sure how loud they are compared to PW or GE engines, but that might account for some of the difference if you're used to the other ones.
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Viscount724
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RE: Loud Engine Noise On CX 744

Fri Oct 10, 2008 8:26 pm

The last few rows on all jets are the noisiest. However I have never thought that 747s were notably loud at the rear. It's also possible that some of the noise could have been due to faulty seals in the rear cabin doors. I've flown on quite a few aircraft where the areas near the doors are very noisy due to poor door seals which causes air to escape with resulting noise.
 
AA737-823
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RE: Loud Engine Noise On CX 744

Fri Oct 10, 2008 9:21 pm



Quoting Spacecadet (Reply 2):
Also, that plane does have RR engines - I'm not sure how loud they are compared to PW or GE engines, but that might account for some of the difference if you're used to the other ones.

I work outside at the busiest 747 airport in the US. I don't know about INSIDE the cabin, as all I've flown on are PW and GE powered, but from outside, RR is DEFINITELY loudest of the three,
 
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HAWK21M
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RE: Loud Engine Noise On CX 744

Sat Oct 11, 2008 1:18 am

From the Information provided,I would suspect Insulation blankets not in place as the culprit  Smile
regds
MEL.
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ImperialEagle
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RE: Loud Engine Noise On CX 744

Sat Oct 11, 2008 1:41 am



Quoting Kappel (Reply 1):
It's because you were sitting in the back, even the a340 is loud in the back. If you sit above or in front of the wings the next time, you'll notice a big difference. It has nothing to do with the age of the aircraft.

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A heavy aircraft with powerful engines is producing some serious thrust to remain at altitude. A seat behind the wing is a good place to experience this issue. The rear of a maxed-out 764 comes to mind. It'll wear you out on a long flight. At the very least get some foam earplugs as it helps reduce the noise fatigue a lot.
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imiakhtar
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RE: Loud Engine Noise On CX 744

Sat Oct 11, 2008 2:44 am

At MTOW for the 744 (875klb), the official engine noise figures at TO for the 3 manufacturers are:

1. GE CF6-80C2B1F = 98.2dB (103.0 dB limit)

2. PW 4056 Package B / Phase I = 98.5dB

3. RR RB211-524H2 = 98.8dB

There's not much in it!

Just to add, the A380 at MTOW is 94dB with RR being slightly quieter.

Regards!
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Sasha
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RE: Loud Engine Noise On CX 744

Sun Oct 12, 2008 3:24 am

Thanks for the tip guys, now I know where to sit to enjoy the noise  Smile
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babaero
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RE: Loud Engine Noise On CX 744

Tue Oct 14, 2008 3:26 pm

I dont think you flew on B-HOZ outbound. Thats already ready been converted to a BCF freighter
 
EMBQA
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RE: Loud Engine Noise On CX 744

Tue Oct 14, 2008 3:33 pm



Quoting Kappel (Reply 1):
It's because you were sitting in the back

BINGO......there is your only answer.
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unattendedbag
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RE: Loud Engine Noise On CX 744

Thu Oct 16, 2008 2:08 am



Quoting Kappel (Reply 1):
It's because you were sitting in the back, even the a340 is loud in the back.



Quoting EMBQA (Reply 10):
BINGO......there is your only answer.

that's probably one reason why "First Class" is in the front.  Smile
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Viscount724
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RE: Loud Engine Noise On CX 744

Thu Oct 16, 2008 2:15 am



Quoting UnattendedBag (Reply 11):
Quoting Kappel (Reply 1):
It's because you were sitting in the back, even the a340 is loud in the back.



Quoting EMBQA (Reply 10):
BINGO......there is your only answer.

that's probably one reason why "First Class" is in the front.

And why it was in the back on propeller types.

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