RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

767 Sound During Loading

Sat Apr 01, 2006 2:03 pm

hey,

I have a question for all the experts out there, this might sound strange but I just enjoy very much hearing all the "bells and whistles" of the aircrafts I travel on. My wife thinks I am nuts...
Any how, every time I am on a 767, I distinctly hear what seems to be a hydraulic hum or some sort of actuator...that just makes the coolest sound...
sort of like a "robot arm" or something
I have noticed it specially when they are loading the bags on the aircraft.
it appears to comes from "below" ...so I was wondering if any one out there knew what it could be...
I know it is not the flaps cause I can identify when those are moved...
is it activated at the cockpit or is it the baggage people??
I am sure it could be a number of things ..but I mainly notice it on the 767...


thanks in advance  airplane 
particles and waves are the same thing, but who knows what that thing is...
 
ikramerica
Posts: 13730
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RE: 767 Sound During Loading

Sat Apr 01, 2006 2:09 pm

well the doors are automatic, but I doubt that's what you are hearing. maybe it's the conveyor on the cargo floor?

Is it constant or occasional?
Of all the things to worry about... the Wookie has no pants.
 
RIHNOSAUR
Topic Author
Posts: 336
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RE: 767 Sound During Loading

Sat Apr 01, 2006 2:16 pm

it's ocasional, i hear it maybe 3-5 times before we pull away from the gate...
particles and waves are the same thing, but who knows what that thing is...
 
stealth777
Posts: 327
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RE: 767 Sound During Loading

Sat Apr 01, 2006 2:20 pm

i think i heard what you speak of last night on my 76 ride. to me it sounded like it came from the cargo hold when they are loading the containers. haven't seen whats down there but it might be a conveyor belt in the plane or something to that nature in the aircraft.
 
abirda
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RE: 767 Sound During Loading

Sat Apr 01, 2006 2:23 pm

If you already associate it with the loading of bags and cargo and it is not constant, it almost certainly is the sound of the conveyor system moving palettes and bins into position. Having only flown on the 767 once, I can't say I know what you're talking about, but then again, I was just excited to be on the way to Hawaii.
 
RIHNOSAUR
Topic Author
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RE: 767 Sound During Loading

Sat Apr 01, 2006 2:29 pm

Quoting Stealth777 (Reply 3):
to me it sounded like it came from the cargo hold when they are loading the containers

yeah yeah!!! and some times the sound stays on for a little longer than other times..but what you guys are saying about the conveyor makes sense...

..cool I am glad were getting closer to the bottom of this!!!

 thumbsup   thumbsup 
particles and waves are the same thing, but who knows what that thing is...
 
ikramerica
Posts: 13730
Joined: Mon May 23, 2005 9:33 am

RE: 767 Sound During Loading

Sat Apr 01, 2006 2:33 pm

It might also be a self leveling mechanism in the gear hydraulics as you load it full of cargo. That's why I asked about periodic, as both those sounds would be periodic.

I know I have felt the 767 level itself, but maybe someone with more knowledge of the bird can share.
Of all the things to worry about... the Wookie has no pants.
 
ha763
Posts: 3168
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RE: 767 Sound During Loading

Sat Apr 01, 2006 2:48 pm

You can hear this on all aircraft with mechanical loading systems. The system is quite loud, it's just that there tends to a lot of other noise to mask it. The following pictures are of the lower deck of the 767. In it you can see the powered wheels to move the ULDs, the roller tracks, locks, guides, etc.


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Photo © Stephan Tophoven
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Photo © Peter Unmuth-VAP

 
COSPN
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RE: 767 Sound During Loading

Sat Apr 01, 2006 3:01 pm

YEs thats it there are kinda Skateboard Tires, that push the containers from the Door to their position; so one man can operate the Loader on the outside and the rollers on the inside..they do seem to be louder than the 747 and DC 10 that use mini tires that seem be more quiet...also if the guy is in a hurry he may forget to de activate the rollers so the 'skateboard' wheels will squeek beacuse they are trying to push a container that is locked in place already..
 
FlyDeltaJets
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RE: 767 Sound During Loading

Sat Apr 01, 2006 6:00 pm

The sould you hear is us moving the containers/and or pallets(only in the front of 767) in and down via the onboard roller system on the plane. All passenger widebodies have this. It makes our job a lot easier.
The only valid opinions are those based in facts
 
lotsamiles
Posts: 254
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RE: 767 Sound During Loading

Sat Apr 01, 2006 6:16 pm

The devices pushing the cargo pallets and containers are called Power Drive Units. They are electric motors with gearboxes and rubber coated rollers that can push with incredible force, up to 500 lbs. force for a unit that can weigh as light as 6 lbs!

Regards,
Lotsamiles
 
FlyDeltaJets
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RE: 767 Sound During Loading

Sat Apr 01, 2006 6:56 pm

Quoting Lotsamiles (Reply 10):
Power Drive Units.

I used the damn thing every day but I couldn't rember the name thanks.
The only valid opinions are those based in facts
 
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HAWK21M
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RE: 767 Sound During Loading

Sun Apr 02, 2006 12:29 am

Sounds like the PDUs operating.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
AvionicMech
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RE: 767 Sound During Loading

Sun Apr 02, 2006 2:13 am

Quoting Ikramerica (Reply 6):
I know I have felt the 767 level itself, but maybe someone with more knowledge of the bird can share.

I work on the 767 everyday and I can assure you there is no self-leveling system on the aircraft. The undrecarriage is bolted to the airframe and it does not have a way of varying the pressure inside the strut to remain level.
 
highflyer9790
Posts: 1189
Joined: Thu Jul 07, 2005 1:21 am

RE: 767 Sound During Loading

Sun Apr 02, 2006 2:39 am

It is the hydrolic system pressurizing. here are some other threads one the same topic...
RE: 717 Noise (by TWAalltheway Mar 27 2006 in Tech Ops)#ID149109
Sound On The MD-80 During Boarding (by TWAalltheway Jun 24 2002 in Tech Ops)

hope it helps..
121
 
SFOMB67
Posts: 371
Joined: Thu Dec 08, 2005 1:20 pm

RE: 767 Sound During Loading

Sun Apr 02, 2006 12:44 pm

Quoting Ikramerica (Reply 6):


I know I have felt the 767 level itself

I think you must be feeling the passengers walking back and forth in the aisles, as I have never heard of any aircraft that levels itself.
Not as easy as originally perceived
 
RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

RE: 767 Sound During Loading

Sun Apr 02, 2006 2:08 pm

Quoting FlyDeltaJets (Reply 11):
I used the damn thing every day but I couldn't remember the name thanks.



Quoting AvionicMech (Reply 13):
I work on the 767 everyday

Thanks every one! it is so cool to get input from people who actually work with these birds!! makes this forum so cool....

Sounds like it is the PDU's,specially since i seem to identify with the 767 which is a wide body..and when they are loading the plane...and I have been many many times on the AA md80 or 717 and really have not heard the same sound...and I am pretty sure the md80's do not have these PDU's...

Quoting HighFlyer9790 (Reply 14):
It is the hydrolic system pressurizing

I recently flew on an A330, and it made a sound (as we were taxiing for take off) that sounded more like what you mention HighFlyer9790...like a humm and thump with a release of pressure at the end....it was pretty unique also!
particles and waves are the same thing, but who knows what that thing is...
 
RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

RE: 767 Sound During Loading

Sun Apr 02, 2006 2:15 pm

Quoting AbirdA (Reply 4):
I was just excited to be on the way to Hawaii.

was this on a delta 767-400???? just curious because when I went to Hawaii (not too long ago) i flew on this bird.....nice.....

cheers  smile 
particles and waves are the same thing, but who knows what that thing is...
 
dl757md
Posts: 1482
Joined: Mon May 24, 2004 9:32 am

RE: 767 Sound During Loading

Sun Apr 02, 2006 8:39 pm

Quoting Ikramerica (Reply 6):
It might also be a self leveling mechanism in the gear hydraulics as you load it full of cargo. That's why I asked about periodic, as both those sounds would be periodic.

I know I have felt the 767 level itself, but maybe someone with more knowledge of the bird can share.

Definitely no leveling system on a 767 or any other commercial passenger A/C that I'm aware of. As a matter of fact as the A/C is loaded the C.G. changes constantly and the pitch of the aircraft changes. The jetways have an auto-level feature to compensate for this. An arm with a wheel at the end extends to touch the fuselage near the door frame after the jetway has been positioned up to the A/C. As the fuselage moves up or down the wheel turns and sends a signal to the jetway auto-level system which repositions the jetway to match the plane. When you are in the jetway and this happens it appears that the aircraft is moving when actually it is the jetway that is moving.

Dl757Md
757 Most beautiful airliner in the sky!
 
AvionicMech
Posts: 308
Joined: Mon Jan 24, 2005 7:28 am

RE: 767 Sound During Loading

Tue Apr 04, 2006 11:37 pm

Quoting Dl757md (Reply 18):
When you are in the jetway and this happens it appears that the aircraft is moving when actually it is the jetway that is moving.

It is actually quite un-nerving when it does this because some of the older jetways are not exactly smooth when they move up and down, it can cause quite a jolt which does cause a few worried looks on some passengers faces.
 
jetset7e7
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RE: 767 Sound During Loading

Wed Apr 05, 2006 12:17 am

Quoting AvionicMech (Reply 19):
It is actually quite un-nerving when it does this because some of the older jetways are not exactly smooth when they move up and down, it can cause quite a jolt which does cause a few worried looks on some passengers faces.

Yes it happened to me when I was boarding a flight from MAN in October, these jetways are quite old.

The only 767 inhold system I work on is Monarch's G-DIMB, everyone hates using it, I don't mind it, its alot easier than the Airbus inhold systems, you can turn off certain drives, and the containers just roll into place with ease with a push.

Mark
Retrofitted Blended Winglets - The Future Is On The Wing
 
AvionicMech
Posts: 308
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RE: 767 Sound During Loading

Wed Apr 05, 2006 12:36 am

Quoting Jetset7E7 (Reply 20):
and the containers just roll into place with ease with a push.

Yeah they may roll into place easily but if the stops aren't put up properly then they also slide around in the hold. We had a 767 a few years ago where someone didn't put the stops up in the forward hold and on take-off the container flew back into the snake pit, otherwise known as the air con bay, and on landing it smashed into the back of the E/E Bay. But we were very lucky and it actually did not cause any major damage.

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