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737 Grinding Noise On Takeoff In The Cabin  
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Posted (4 years 2 months 1 week 4 days 8 hours ago) and read 7726 times:

I kept on pushing this back and back but today I finally decided to do it. Back in February I flew MIA-DCA to see the snow right after the 2 consecutive blizzards that passed through the DC area.

I was happy to be going up to the snow and I was also happy to have a seat in F.

As much as I love flying I am still a bit nervous so as we took off it sure didn't help to have a strong crosswind together with this incredibly strange grinding noise. Fortunately I had my camera out so you can see and hear the video I took during take off rather than explaining what the sound was like. The sound starts at around 11 seconds. Thanks for your help!

Uploaded to youtube today: http://www.youtube.com/watch?v=-pqurfZCSFc

Аэрофлот001
Искренне Ваш

27 replies: All unread, showing first 25:
 
User currently offlineSpacepope From Vatican City, joined Dec 1999, 2930 posts, RR: 1
Reply 1, posted (4 years 2 months 1 week 4 days 8 hours ago) and read 7712 times:

Sounds like it started right at rotation. Nosewheel out of balance?


The last of the famous international playboys
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Reply 2, posted (4 years 2 months 1 week 4 days 7 hours ago) and read 7630 times:

Yes the fact that it started at rotation is what made it more worrying.

User currently offlineyvphx From United States of America, joined Jul 2009, 258 posts, RR: 0
Reply 3, posted (4 years 2 months 1 week 4 days 7 hours ago) and read 7610 times:

I agree its the nose wheel. When I fly my little c-172 if I don't tap the breaks after liftoff I get that same sound and vibration, to a smaller extent of course.

User currently offlineAtlwest1 From United States of America, joined Jan 2009, 1046 posts, RR: 1
Reply 4, posted (4 years 2 months 1 week 4 days 7 hours ago) and read 7577 times:

Hey i just listened to the sound and its totally nothing to be allarmed about. It is the noise of the gears retracting specifically the forward gear. I hear it on a daily basis. Fiirst time I heard it, it was startling but its all good   Just sit back relax and enjoy your flight.  


ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co. or Airt
User currently offlinejpetekyxmd80 From United States of America, joined Jul 2003, 4389 posts, RR: 29
Reply 5, posted (4 years 2 months 1 week 4 days 7 hours ago) and read 7577 times:

I noticed nearly the exact same thing the first time I flew an AA 738 in F. Freaked me out a bit as well!


The Best Care in the Air, 1984-2009
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Reply 6, posted (4 years 2 months 1 week 4 days 6 hours ago) and read 7446 times:

The reason it startled me so much though was because I had previously flown in F on the 737 with AA and never heard that noise. When the gear would go up I would just hear something like a small motor. Just a few weeks ago I flew to IAD up front and no loud vibrating noise and then on IAD-SJU no vibrating noise either. Anyways thanks for the help!

User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4491 posts, RR: 21
Reply 7, posted (4 years 2 months 1 week 4 days 6 hours ago) and read 7383 times:

Quoting Atlwest1 (Reply 4):
Hey i just listened to the sound and its totally nothing to be allarmed about. It is the noise of the gears retracting specifically the forward gear. I hear it on a daily basis.

Specifically it sounds like the nosewheel tires slowly spinning down as the assembly no longer supports weight on rotation.

You can hear it on just about any aircraft if you're sitting in the right place.



I got my head checked--by a jumbo jet
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Reply 8, posted (4 years 2 months 1 week 4 days 6 hours ago) and read 7356 times:

Quoting JBirdAV8r (Reply 7):
Specifically it sounds like the nosewheel tires slowly spinning down as the assembly no longer supports weight on rotation.

But why would it make such a loud noise though?


User currently offlineCO777DAL From United States of America, joined Feb 2007, 616 posts, RR: 0
Reply 9, posted (4 years 2 months 1 week 4 days 5 hours ago) and read 7254 times:

Quoting Spacepope (Reply 1):
Yes the fact that it started at rotation is what made it more worrying.

Watched your video and heard the noise. Puzzling! What I find odd is that I'm in First all the time on Continental 737s and never heard that sound. CO has a ton of 737s. I also have a over a hundred videos and can't remember ever hearing it on on any of them. It was very loud in your AA video. Other have said they hear it on AA. Could CO have something the pilots do so it doesn't make that sound. I just find it odd, in my hundreds of flight with CO I have never heard what you recorded on AA.



Worked Hard. Flew Right. Farewell, Continental. Thanks for the memories.
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Reply 10, posted (4 years 2 months 1 week 4 days 4 hours ago) and read 7158 times:

Quoting JBirdAV8r (Reply 7):
Specifically it sounds like the nosewheel tires slowly spinning down as the assembly no longer supports weight on rotation.

But why would it make such a loud noise though?

Quoting CO777DAL (Reply 9):
Watched your video and heard the noise. Puzzling! What I find odd is that I'm in First all the time on Continental 737s and never heard that sound. CO has a ton of 737s. I also have a over a hundred videos and can't remember ever hearing it on on any of them. It was very loud in your AA video. Other have said they hear it on AA. Could CO have something the pilots do so it doesn't make that sound. I just find it odd, in my hundreds of flight with CO I have never heard what you recorded on AA.

Exactly how I feel


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5831 posts, RR: 11
Reply 11, posted (4 years 2 months 1 week 4 days 3 hours ago) and read 7009 times:

I have watched your video, and know exactly what the issue is.
The issue is an out-of balance nosewheel. This is most commonly caused by uneven wear on the tires, which have the added strain of steering the aircraft (compared to the mains, I mean) and so often wear in strange patterns.
For this problem, the only remedy is a dual nosewheel replacement. That's cost ineffective, so most carriers will let it go until the tires actually need to be replaced. It doesn't hurt anything, it just makes the airplane sound cheap!
The balance weights sometimes fall off of the wheels. They shouldn't, but I've seen it happen.

Quoting JBirdAV8r (Reply 7):
Specifically it sounds like the nosewheel tires slowly spinning down as the assembly no longer supports weight on rotation.

Yup- hence the frequency of the vibes diminishes... I think you're exactly right.

Quoting Aeroflot001 (Reply 8):
But why would it make such a loud noise though?

Because they're relatively heavy, and turning at a very high rate, and have nowhere to transmit their vibrational loads to but INTO THE AIRFRAME.

Quoting CO777DAL (Reply 9):
Could CO have something the pilots do so it doesn't make that sound. I just find it odd, in my hundreds of flight with CO I have never heard what you recorded on AA.

Nope. In fact, CO's 737-9ER aircraft ALL seem to make an odd nose wheel noise, from about 30 mph on to gear up. At least, all the ones I've ever flown on have. Which is odd to me, because their -900's don't make that noise.

Anyhow, all this is the opinion of a 737NG mechanic (although not for CO, nor-as my username would imply- for AA).


User currently offlineAeroflot777 From Russia, joined Mar 2004, 3008 posts, RR: 26
Reply 12, posted (4 years 2 months 1 week 4 days 2 hours ago) and read 6953 times:

Sounded like something out of LOST.

Aeroflot777


User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Reply 13, posted (4 years 2 months 1 week 4 days 1 hour ago) and read 6882 times:

Quoting AA737-823 (Reply 11):
I have watched your video, and know exactly what the issue is.
The issue is an out-of balance nosewheel. This is most commonly caused by uneven wear on the tires, which have the added strain of steering the aircraft (compared to the mains, I mean) and so often wear in strange patterns.
For this problem, the only remedy is a dual nosewheel replacement. That's cost ineffective, so most carriers will let it go until the tires actually need to be replaced. It doesn't hurt anything, it just makes the airplane sound cheap!
The balance weights sometimes fall off of the wheels. They shouldn't, but I've seen it happen.

Phenomenal response now I really understand what was going on.

Quoting Aeroflot777 (Reply 12):
Sounded like something out of LOST.

Aeroflot777

Not something you want to think about in the air, очень не хорошо!


User currently offlineSpacepope From Vatican City, joined Dec 1999, 2930 posts, RR: 1
Reply 14, posted (4 years 2 months 1 week 3 days 21 hours ago) and read 6613 times:

Quoting AA737-823 (Reply 11):
I have watched your video, and know exactly what the issue is.
The issue is an out-of balance nosewheel. This is most commonly caused by uneven wear on the tires, which have the added strain of steering the aircraft (compared to the mains, I mean) and so often wear in strange patterns.

Yay, I guessed right!

Had this happen with one of the maingear tires on the LH 744 I flew last fall. Those things shake pretty bad since they are so large. Concerned a lot of passengers. Luckily it stopped quickly when the retraction sequence started.



The last of the famous international playboys
User currently offlineRussianJet From Belgium, joined Jul 2007, 7703 posts, RR: 21
Reply 15, posted (4 years 2 months 1 week 3 days 21 hours ago) and read 6591 times:
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Nonsense to all of your theories, it was the crew busy grinding coffee ready for those demanding F pax.


✈ Every strike of the hammer is a blow against the enemy. ✈
User currently offlineMadDogJT8D From United States of America, joined Oct 2009, 398 posts, RR: 1
Reply 16, posted (4 years 2 months 1 week 3 days 20 hours ago) and read 6537 times:

I've felt vibrations in the forward cabin of the 767 right after rotation as well until the gear has been retracted. The first time, I wondered what it was, but after a few flights I got used to it. Nothing to be alarmed about - airframes are designed to handle certain amounts of vibration.

User currently offlineChase From United States of America, joined Nov 2005, 1054 posts, RR: 0
Reply 17, posted (4 years 2 months 1 week 3 days 20 hours ago) and read 6460 times:

Not to be a jerk, but why were you taking video at liftoff, when electronic devices are not allowed to be used?

User currently offlineAA737-823 From United States of America, joined Mar 2000, 5831 posts, RR: 11
Reply 18, posted (4 years 2 months 1 week 3 days 18 hours ago) and read 6317 times:

Quoting Spacepope (Reply 14):
Had this happen with one of the maingear tires on the LH 744 I flew last fall. Those things shake pretty bad since they are so large. Concerned a lot of passengers. Luckily it stopped quickly when the retraction sequence started.

Mains will stop vibrating more quickly. When the gear handle is put into the UP position, part of the retraction sequence is a quick, short application of the brakes. This stops them from rotating, the fear being that IF a tire were to have blown, you really don't want it spinning at 150+ MPH inside the wheel well, where large sections of tread could easily start slapping out hydraulic lines and so forth.
The nosewheel doesn't have a brake on most modern air transports (nosewheel brakes were optional on certain 727 aircraft, as was Jet-Assisted-Takeoff). So, instead, there are snubbers in the ceiling of the nosewheel well, and they rub on the nose tires quite firmly, applying sufficient friction to stop the tires pretty quick. BUT anyhow, mains are stopped before they enter the well, noses after.
The nose wheel snubbers are most noticeable on 757 aircraft... the entire first class cabin shakes like crazy when I fly on those birds!

Anyhow, good day all.


User currently offlineGoldenshield From United States of America, joined Jan 2001, 6039 posts, RR: 14
Reply 19, posted (4 years 2 months 1 week 3 days 18 hours ago) and read 6286 times:

Quoting AA737-823 (Reply 18):
The nose wheel snubbers are most noticeable on 757 aircraft... the entire first class cabin shakes like crazy when I fly on those birds!

They would also be noticable to passengers flying in the nose of a 747.



Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineaviatorcraig From United Kingdom, joined Mar 2010, 220 posts, RR: 0
Reply 20, posted (4 years 2 months 1 week 3 days 18 hours ago) and read 6247 times:

Quoting AA737-823 (Reply 18):
The nosewheel doesn't have a brake on most modern air transports (nosewheel brakes were optional on certain 727 aircraft, as was Jet-Assisted-Takeoff).

I thought all 727s had jet assisted take-off!   

Some that were used for hot and high ops (e.g. Mexicana) had rocket assisted take-off as well



707 727 Caravelle Comet Concorde Dash-7 DC-9 DC-10 One-Eleven Trident Tristar Tu-134 VC-10 Viscount plus boring stuff!
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5831 posts, RR: 11
Reply 21, posted (4 years 2 months 1 week 3 days 10 hours ago) and read 5891 times:

Quoting aviatorcraig (Reply 20):
I thought all 727s had jet assisted take-off!   

Some that were used for hot and high ops (e.g. Mexicana) had rocket assisted take-off as well

FINE FINE FINE, get all technical on me why don't ya?!?! Come to think of it, the acronym is JATO If it's rockets (which it is), shouldn't it be RATO? Rockets are, in fact, a type of jet engine- they're not a GTE (gas turbine engine), but they do produce a jet of exhaust gases, which makes them.... a jet engine.
So... now that that's clear as mud!!!

Quoting Goldenshield (Reply 19):
They would also be noticable to passengers flying in the nose of a 747.

It's noticeable to any passenger sitting in the forward cabin of any aircraft equipped with a retractable nosewheel. My point was simply that the 757 makes a particularly pronounced noise.


User currently offlineDaysleeper From UK - England, joined Dec 2009, 841 posts, RR: 1
Reply 22, posted (4 years 2 months 1 week 3 days 9 hours ago) and read 5818 times:

Quoting AA737-823 (Reply 21):
FINE FINE FINE, get all technical on me why don't ya?!?! Come to think of it, the acronym is JATO If it's rockets (which it is), shouldn't it be RATO? Rockets are, in fact, a type of jet engine- they're not a GTE (gas turbine engine), but they do produce a jet of exhaust gases, which makes them.... a jet engine.
So... now that that's clear as mud!!!

If you have a look towards the bottom of the wiki page here http://en.wikipedia.org/wiki/JATO both JATO and RATO are used to describe what looks like the same thing... so yeah clear as mud  

I never knew these were an option on the 727 though, does anyone know if any airline ever used them in service? I mean personally (and im sure im not alone on here) I would have loved to experiance a JATO take off and actually gone out of my way too, but i'd imagine it would be a little scary for the average pax.... and for a nervous flyer.....

I guess also, unless there was a way to jettison them in a safe manner then there would be no possible way to abort take off once they are lit..


User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4491 posts, RR: 21
Reply 23, posted (4 years 2 months 1 week 3 days 8 hours ago) and read 5714 times:

Quoting Chase (Reply 17):
Not to be a jerk, but why were you taking video at liftoff, when electronic devices are not allowed to be used?

Not to be a jerk? What do you expect his response to be? What do you want it to be?

Quoting aviatorcraig (Reply 20):
thought all 727s had jet assisted take-off!

Some that were used for hot and high ops (e.g. Mexicana) had rocket assisted take-off as well

JATO is a technically correct term. And actually, JATO is by far the most commonly used description for...we'll call it takeoff assisted by alternative propulsion devices. Besides, "jet" can be defined as the "occurrence of a sudden discharge"--which fits the bill of a rocket, no?



I got my head checked--by a jumbo jet
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 403 posts, RR: 0
Reply 24, posted (4 years 2 months 1 week 3 days 8 hours ago) and read 5687 times:

Quoting Chase (Reply 17):
Not to be a jerk, but why were you taking video at liftoff, when electronic devices are not allowed to be used?

Because American Airlines allowed a filming of a documentary on board one of its aircraft American Airlines a Week in the life during takeoff and its clearly shown.


Interesting to see that many others have experienced this, and reassuring as well


25 Goldenshield : My point was that those passengers sit right ABOVE the wheel well. For the 757, it's most likely because the mount for the nose wheel is right below
26 BY738 : Shouldnt this be in the technical forum along with all the other 737 grinding noises questions?
27 Post contains images aviatorcraig : On this side of the pond it is RATO Accepted usage here is Rocket Assisted Take Off for things that once lit cannot be turned off until they are done
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