Aircraft Shudders

[Walter Sim 1]

Hey there, from my recent two flight i realised something odd. Its on the 737 and 747 of MH. Right after takeoff there is this shudder, a sudden vibration of the cabin. It lasts for a few seconds then it slowly dissapear. What causes this to happen and is it harmful?

 

Thanks

[Guest Fendy]

you're still here today, so i doubt its harmful. maybe its the gear...

[Imran K. 0]

Hey there, from my recent two flight i realised something odd. Its on the 737 and 747 of MH. Right after takeoff there is this shudder, a sudden vibration of the cabin. It lasts for a few seconds then it slowly dissapear. What causes this to happen and is it harmful?

 

Thanks

10045[/snapback]

 

Happens on the T7 as well...have had to endure that everytime i fly home...

[S V Choong 4]

I heard of that before on 9M-MPA, I suspect it is when the gate of the landing gate opens and when the gear retracts it will make that noise. On other flights it does do that and I thought it was something to do with 9M-MPA's age.

[Norman 1]

I heard of that before on 9M-MPA, I suspect it is when the gate of the landing gate opens and when the gear retracts it will make that noise.  On other flights it does do that and I thought it was something to do with 9M-MPA's age.

10051[/snapback]

 

It's the vibrations from "unbalanced" wheels spinning before the pilot apply brake

You'll notice that also if you car wheels (especially front ones) are not balanced

hehehe kidding...

 

I'm thinking similarly to Fendy & SV there... the gear-well's doors I guess...

[Gavin Andrew David 6]

any sound in an aircraft just rocks doesn't it

[S V Choong 4]

Last time I was sitting at 29A onboard 9M-MPA, that noisy was pretty appearant and it makes you felt like the crew preparation compartment have things fell apart during take off.....

 

But I think it doesn't do that on the 777s right???? Haven't heard it on A330s either.

 

There's one funny noise onboard the Qantas and Air NZ 733. You can vaguely hear a metal grinding sound constantly, felts like the sound of some warning system. May be the cargo door wasn't shut properly or something like that. Throughout the flight, my passenger at the seat next to me asked me the very same question and we had no idea what it was. I have came across on two 733, Air NZ and Qantas each. Haven't had that on MAS 734 yet. Could be quite scary....... Have u guys heard that before? Perhaps Capt. Radzi could shed some light on this.......

Edited October 13, 2005 by S V Choong

[Pieter C. 5]

It happens as well when seated in the C-class on KLM 747's (nose-section): it's the nose-wheel retracting and then the tires will hit the brakes inside the wheel-well, making a shudder...just my 2 sen

[Walter Sim 1]

yar, it happens during gear retraction to be preetysure, because i can here the KNOCK sound of the wheels getting deployed. But if i've not mistaken these sound only happen in MH? as far as my airline experience is with qantas, thai, rb, ba there are none of these sounds.

[Gavin Andrew David 6]

I believe its the brakes because there's no ground noise to drown out the sound of the brakes compared to when there is braking on the ground

[Sandeep G 1]

its to do with the wheels spinning furiously after take off. As there is no reaction force from the ground once the aircraft is just airborne, the spinning wheels cause a 'gyroscopic effect' and this translates to the shudder you feel as you take off.. the shudder is only for a moment whilst the brake is applied to stop the wheels spinning for retraction.. if there was no brakes, you would feel this shudder far more violently should the wheels be retracted.

 

[Tony 1]

agree with Sandeep. gear retraction will make noise, but don't think that'll contribute to any of the vibrations we're talking about here - the spinning wheels sound more plausible.

[Sandeep G 1]

Thanks Tony, A simple test that you can do at home is get a bicycle wheel (you'll have to detach it first

 

Then, get a bit of tube about 20-30 cm long and attach that to the centre of the wheel. Then sit yourself on a chair that can spin around. Hold the wheel out by the tube at the end furthest from the wheel. With the other hand, spin the wheel fast!!! KEEP YOUR FEET OFF THE FLOOR! The comnbination of moments resulting from the forces being applied will spin you in the chair This is the gyroscopic effect.

 

Then, you can realise why with some many wheels, you feel that shudder on an aircraft

 

BTW, I believe the Shudder is more pronounced in MH cabins due to a slight difference in interior fittings... On SQ for example, there is more dampening of the interior fittings resulting in a lower tendency to shudder... This adds to weight of course which is possibly why MH has yet to invest in such fittings. Also, if the wheel brakes are INOP and the wheels are left to cool and stop spinning by themselves, this will result in increased shudder.

 

Don't quote me on the difference between MH and SQ cabins, maybe if we have any engineers here they can let us know

[Denny Yen 0]

I encountered this phenomenon several times. 2 years ago on CX 744 from TPE-NRT. The vibration came from beneath us a short while after take-off.

 

After it stopped, the pilot announced on the PA that it was due to leaving the landing-gears for a longer time-period before retracting them. Reason: abnormal temperatures in the main-gears. Its a good practice on CX's part to keep us informed about what's going on.

 

I experienced this again last week on EVA's 744 YVR-TPE, the vibration is also felt in the front section of EVA Air's older 744 too, as Pieter had pointed out.