gopal
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Effect Of Cabin Bags On Airframe

Thu Dec 16, 2010 4:58 pm

As more are more Airlines are charging for Checked-in baggage travellers are carrying as much as they can in their cabin bags. Therefore cabin bags are not only getting bigger, but also heavier. It is getting to the point where one cabin bag takes up almost an entire overhead bin compartment with remaining room for a small handbag utmost.

Question to the informed members of this forum is: Is this causing undue strain on the overhead bins, which in turn will transfer the strain on the dome of the airframe ? Underbelly cargo compartments on commercial airliners (especially the long haul ones) are built with proper reinforcements for storage of large, bulky suitcases and other cargo. But the overhead bins are not designed to carry such heavy loads. Will airlines need to conduct more frequent B anc C checks on their airplanes as a result of this behavior on part of the travelling public ?
 
Fly2HMO
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RE: Effect Of Cabin Bags On Airframe

Thu Dec 16, 2010 5:28 pm

Quoting gopal (Thread starter):
Therefore cabin bags are not only getting bigger, but also heavier.

I fail to see where you drew this conclusion from. Carry on bags have size constraints manufacturers adhere to. And every airline has a little box where you can measure your bags. If anything, people are cramming as much stuff as they can into their bags, but last time I checked the standard carry-on bag has not increased in size at all.

Quoting gopal (Thread starter):
But the overhead bins are not designed to carry such heavy loads.

Says who? There would've been numerous cases of overhead bins falling on passengers and cracking their skulls by now if this was true  

Every overhead bin I've seen has a placard stating the maximum designed weight limit. I want to say I remember a limit of well over 100lbs on a 737 bin. There's a reason goofy flight attendants frequently take pictures of themselves inside the bins without breaking them.

Quoting gopal (Thread starter):
Will airlines need to conduct more frequent B anc C checks on their airplanes as a result of this behavior on part of the traveling public ?

No. Apples and oranges.

[Edited 2010-12-16 09:33:59]
 
roseflyer
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RE: Effect Of Cabin Bags On Airframe

Thu Dec 16, 2010 5:42 pm

Heavier cabin bags are causing damage to stowbin doors & latches. I have seen numbers that replacements of these items directly went up after airlines started charging for the first checked bag, however the replacement costs & associated delays are far less than the increased revenue.

The bins are designed usually for a max of 160lbs load. That's about 4 full rollaboard suitcases which is the max that will fit in a bin. Unless a bag is particularly overweight, there is no problem. It is quite difficult for a cabin bag to be over 40lbs. Although they are not weighed, the physical space does limit them. 160lbs is also a fatigue load, so a one heavily overweight bag won't do anything.

As far as increasing C or D checks, airlines do not plan these checks on specific items. If a particular item is failing more often in service, or cracks/fatigue damage/etc is found to be more prevailent during inspections, the item is typically changed to be replaced/inspected more frequently such as transitioning from D check to C check. Airline maintenance programs are fairly robust.
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bikerthai
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RE: Effect Of Cabin Bags On Airframe

Thu Dec 16, 2010 7:38 pm

Quoting RoseFlyer (Reply 2):
Heavier cabin bags are causing damage to stowbin doors & latches.

This is the key point. If there would be a failure, most likely the failure would occur on the composite bin at the hinge or clevis attach point. Thus any failure would be isolated to the bin and not be driven to structure. Hopefully any single point failure on the bin would re-distribute the load to other attach points on the bin assembly with the bin deforming enough to let crew know to replace it.

bikerthai
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roseflyer
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RE: Effect Of Cabin Bags On Airframe

Thu Dec 16, 2010 8:10 pm

Quoting bikerthai (Reply 3):
Hopefully any single point failure on the bin would re-distribute the load to other attach points on the bin assembly with the bin deforming enough to let crew know to replace it.

In all my years of working on airplanes, I have never heard of an attachment to a bin failing to the point that it was evident to a crew member. The bins have to sustain 9~16Gs of direct force with 150% of max load. They are tested to that requirement. They don't break. The latches, doors and hinges are a different story all together.
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gopal
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RE: Effect Of Cabin Bags On Airframe

Fri Dec 17, 2010 3:39 pm

Quoting RoseFlyer (Reply 2):
The bins are designed usually for a max of 160lbs load. That's about 4 full rollaboard suitcases which is the max that will fit in a bin. Unless a bag is particularly overweight, there is no problem. It is quite difficult for a cabin bag to be over 40lbs. Although they are not weighed, the physical space does limit them. 160lbs is also a fatigue load, so a one heavily overweight bag won't do anything.

It is assuring to note that the overhead bins are built strong enough carry such heavy loads.

The size of cabin bag does limit its weight but from my experience airlines do not enforce the cabin baggage size check very strictly. During a recent long haul flight I noticed that many of the cabin bags being brought in would definetely not have fit into the size check box kept near the check in counter. Also sometimes density of the items being carried in a cabin bag can make it quite heavy. For example - books, expecially hard cover text books can quickly take a bag's weight over the 40 lb limit.
 
citationjet
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RE: Effect Of Cabin Bags On Airframe

Fri Dec 17, 2010 4:03 pm

Quoting RoseFlyer (Reply 4):
In all my years of working on airplanes, I have never heard of an attachment to a bin failing to the point that it was evident to a crew member. The bins have to sustain 9~16Gs of direct force with 150% of max load. They are tested to that requirement. They don't break. The latches, doors and hinges are a different story all together.

I agree completely. The attachment points for the overhead bins are sized to meet the crash load requirements for a loaded bin. The much lower loads during flights even with heavier loads is much lower.

As far as the latches, doors and hinges, the airline can easily cover the costs of these items from the increased fees they are charging for checked bags. They are the ones who have created this issue by instituting checked bag fees.
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bikerthai
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RE: Effect Of Cabin Bags On Airframe

Fri Dec 17, 2010 11:14 pm

Quoting RoseFlyer (Reply 4):
They don't break.

LOL, in my limited years in Closets . . . I have seen attach point joints break (the composite part). But that was when we tested beyond the required 9G loading, and when some of the other stuff (hinges, panels, brackets) gave way. But that is also a different story . . .

bikerthai
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SchorschNG
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RE: Effect Of Cabin Bags On Airframe

Sat Dec 18, 2010 10:42 am

Quoting RoseFlyer (Reply 4):
In all my years of working on airplanes, I have never heard of an attachment to a bin failing to the point that it was evident to a crew member. The bins have to sustain 9~16Gs of direct force with 150% of max load. They are tested to that requirement. They don't break. The latches, doors and hinges are a different story all together.

Fun fact: the bins accept less vertical acceleration than the seats below. So, in case of a crash, the passengers might be killed by overhead bins crashing down. Has happened.
From a structural standpoint, passengers are the worst possible payload. [Michael Chun-Yung Niu]
 
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UltimateDelta
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 21, 2010 12:30 am

Quoting RoseFlyer (Reply 2):
Heavier cabin bags are causing damage to stowbin doors & latches

Just as a note- On a recent CRJ-900 flight, someone tried to stuff an bag that was a little too big for the bin and in trying to squash it shut, broke the latch. 20 minutes, some aerospace-grade duct tape and a 'Do Not Open' sticker got us on our way.
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roseflyer
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 21, 2010 4:42 pm

Quoting UltimateDelta (Reply 9):

Just as a note- On a recent CRJ-900 flight, someone tried to stuff an bag that was a little too big for the bin and in trying to squash it shut, broke the latch. 20 minutes, some aerospace-grade duct tape and a 'Do Not Open' sticker got us on our way.

Stowbins are in the top 5 reasons for why flights get delayed. It is pretty easy to move bags so that the bin can be left empty, but the time required to get a mechanic to "secure the door" is a leading cause of delays.
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HAWK21M
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 21, 2010 7:43 pm

Quoting gopal (Thread starter):
cabin bags are not only getting bigger, but also heavier

There is a restriction on Dimension & Weight of allowable cabin bages or hand bags.
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Viscount724
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RE: Effect Of Cabin Bags On Airframe

Fri Dec 24, 2010 12:56 am

Quoting HAWK21M (Reply 11):
Quoting gopal (Thread starter):
cabin bags are not only getting bigger, but also heavier

There is a restriction on Dimension & Weight of allowable cabin bages or hand bags.

Some carriers (EasyJet for one) has the usual limit on carry-on bag dimensions but no weight limit. If you can lift it, you can carry it on. BA also has no weight limit on carry-on bags. The only restriction is that you have to be able to lift it into the overhead bin unaided.
 
SP90
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RE: Effect Of Cabin Bags On Airframe

Sun Dec 26, 2010 4:56 pm

OK most people's carry-on consists of lightweight stuff like clothes, a book or two, maybe a laptop. What if there was a coin collector's convention and a majority of the carry-on were filled with coins? Bags packed with small dense objects like these would surely throw off the standard weight assumptions of a carry-on bag right? Has there ever been a flight where this has been a problem?
 
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HAWK21M
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 28, 2010 11:04 am

Quoting Viscount724 (Reply 12):
The only restriction is that you have to be able to lift it into the overhead bin unaided.

I'm sure the Ground staff can ask for a weighing check if suspected to be heavy.
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hal9213
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 28, 2010 12:33 pm

Quoting SchorschNG (Reply 8):

Fun fact: the bins accept less vertical acceleration than the seats below. So, in case of a crash, the passengers might be killed by overhead bins crashing down. Has happened.

Thats why they invented the brace position 
Quoting SP90 (Reply 13):
What if there was a coin collector's convention and a majority of the carry-on were filled with coins?

Read too much of Dagobert Duck, eh ?  
Seriously, the density might be higher, but even as a collector, would you want to carry around a bag with 40 Pounds (weight, not sterling  ) worth of coins ?
 
ronglimeng
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 28, 2010 1:29 pm

I have found this thread to be very interesting as it discusses some questions I posed in a recent trip report I did after flying Delta DTW-PVG return.

I've saw those carry-on size-check boxes but they apparently aren't used. There may be so-called "standard carry-on bag sizes" but I have strong suspicions that passengers are pushing the envelope. As far as a requirement that passengers have to lift their own bags unaided, that was not met in about half the cases on my flights.

After boarding announcements, there was probably no control on all but the most egregious examples of over-sized carry on items, a general rush to board followed by a free-for-all to fill the available bins, passenger arguments about space entitlements, harried flight attendants trying to assist, and finally cabin announcements that any cabin baggage that couldn't be stowed, would be checked for free.

Based on what "Roseflyer" is saying above, I'll be staying out of the aisle seats, as that is where I'm likely to get conked on the head as a result of a failed bin latch or hinge.
 
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Starlionblue
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RE: Effect Of Cabin Bags On Airframe

Tue Dec 28, 2010 2:10 pm

Quoting Viscount724 (Reply 12):
BA also has no weight limit on carry-on bags

Sort of. The limit is "You must be able to lift the bag into the overhead locker unaided"
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