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Effect Of Cabin Bags On Airframe  
User currently offlinegopal From United States of America, joined Jun 1999, 113 posts, RR: 0
Posted (3 years 4 months 1 week 3 days 8 hours ago) and read 5330 times:

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 ?

17 replies: All unread, jump to last
 
User currently offlineFly2HMO From , joined Dec 1969, posts, RR:
Reply 1, posted (3 years 4 months 1 week 3 days 7 hours ago) and read 5307 times:

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]

User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9385 posts, RR: 52
Reply 2, posted (3 years 4 months 1 week 3 days 7 hours ago) and read 5293 times:

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.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlinebikerthai From United States of America, joined Apr 2010, 2014 posts, RR: 4
Reply 3, posted (3 years 4 months 1 week 3 days 5 hours ago) and read 5231 times:

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



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9385 posts, RR: 52
Reply 4, posted (3 years 4 months 1 week 3 days 5 hours ago) and read 5217 times:

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.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlinegopal From United States of America, joined Jun 1999, 113 posts, RR: 0
Reply 5, posted (3 years 4 months 1 week 2 days 9 hours ago) and read 4988 times:

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.


User currently offlineCitationJet From United States of America, joined Mar 2003, 2372 posts, RR: 3
Reply 6, posted (3 years 4 months 1 week 2 days 9 hours ago) and read 4966 times:

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.



Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
User currently offlinebikerthai From United States of America, joined Apr 2010, 2014 posts, RR: 4
Reply 7, posted (3 years 4 months 1 week 2 days 2 hours ago) and read 4867 times:

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



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineSchorschNG From Germany, joined Sep 2010, 500 posts, RR: 0
Reply 8, posted (3 years 4 months 1 week 1 day 14 hours ago) and read 4752 times:

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]
User currently offlineUltimateDelta From United States of America, joined Sep 2007, 2064 posts, RR: 6
Reply 9, posted (3 years 4 months 6 days ago) and read 4448 times:

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.



Midwest Airlines- 1984-2010
User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9385 posts, RR: 52
Reply 10, posted (3 years 4 months 5 days 8 hours ago) and read 4321 times:

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.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlineHAWK21M From India, joined Jan 2001, 31580 posts, RR: 57
Reply 11, posted (3 years 4 months 5 days 5 hours ago) and read 4266 times:

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.
regds
MEL.



Think of the brighter side!
User currently onlineViscount724 From Switzerland, joined Oct 2006, 24117 posts, RR: 23
Reply 12, posted (3 years 4 months 3 days ago) and read 4071 times:

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.


User currently offlineSP90 From United States of America, joined May 2006, 388 posts, RR: 0
Reply 13, posted (3 years 4 months 8 hours ago) and read 3834 times:

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?

User currently offlineHAWK21M From India, joined Jan 2001, 31580 posts, RR: 57
Reply 14, posted (3 years 3 months 4 weeks 14 hours ago) and read 3652 times:

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.
regds
MEL.



Think of the brighter side!
User currently offlinehal9213 From Germany, joined May 2009, 302 posts, RR: 0
Reply 15, posted (3 years 3 months 4 weeks 12 hours ago) and read 3635 times:

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 ?


User currently offlineronglimeng From Canada, joined Oct 2006, 625 posts, RR: 0
Reply 16, posted (3 years 3 months 4 weeks 11 hours ago) and read 3627 times:

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.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 17, posted (3 years 3 months 4 weeks 11 hours ago) and read 3623 times:

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"



"There are no stupid questions, but there are a lot of inquisitive idiots."
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