Inflated Football in cabin?
Joined: Jun 2005
Posts: 61
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From: Northumberland N55 W02
>>Standard football pressure is around 13psid - cabin pressure at SL is about 14.7 psi and at 8000' cabin altitude about 10psi - so there's only an extra 4-5 odd psi on a football that's designed to take 28psi (absolute).
>>I may have got diff and abs confused there, apologies. But it's not a big difference anyway, IMHO.
>>In any case, like balloons, if a football did burst it wouldn't explode outwards like a bomb - if you watch high-speed film of balloons bursting, the failure begins with a small rip or hole and the skin retracts along itself, not expanding outwards.
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Woa there. If a gauge measures 13 psi within the football this is in addition to 14.7 psi atmospheric. Where do you get the 28 psi 'absolute figure from (and how would you measure it - in a vacuum?)?
Balloons retract because they are elastically stretched when inflated. Puncturing them releases the forces keeping the balloon stretched, so it implodes. A football tends to be rigid (within limits) and so explosive destruction could propel pieces outwards as the internal pressure escapes. It's the principle of a bomb . . .
>>I may have got diff and abs confused there, apologies. But it's not a big difference anyway, IMHO.
>>In any case, like balloons, if a football did burst it wouldn't explode outwards like a bomb - if you watch high-speed film of balloons bursting, the failure begins with a small rip or hole and the skin retracts along itself, not expanding outwards.
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Woa there. If a gauge measures 13 psi within the football this is in addition to 14.7 psi atmospheric. Where do you get the 28 psi 'absolute figure from (and how would you measure it - in a vacuum?)?
Balloons retract because they are elastically stretched when inflated. Puncturing them releases the forces keeping the balloon stretched, so it implodes. A football tends to be rigid (within limits) and so explosive destruction could propel pieces outwards as the internal pressure escapes. It's the principle of a bomb . . .
Joined: Oct 2002
Posts: 291
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From: Heathrow
Woa there. If a gauge measures 13 psi within the football this is in addition to 14.7 psi atmospheric.
If a ball can be inflated to 28PSI gauge pressure, then it will survive (in the case above).
A beach ball would not survive as large a change in pressure as a football, so deflating it would be sensible and easy.
On a flight I operated one day the Ccrew brought up a football and asked us about it. We were unable to deflate it and so we stuck it in a wardrobe cautioning the passenger that it might burst. At the end of the flight it was fine. I wouldn't want to be next to a bursting football, hence putting it in the wardrobe.
No one has yet mentioned that a ball will expand as the pressure inside increases. In this case it is likely to have a negligible effect though!
Joined: Apr 2005
Posts: 801
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From: Southeast USA
I would say, Yes, we have reached a consensus.
Those who are legitimately concerned that a fully and properly inflated football might uncontrollably expand at the cabin altitudes maintained in modern aircraft and are likely to explode and do damage to the aircraft and/or injure persons on board will do all that is necessary to deflate said football or have the estranged passenger FedEx or UPS the potential “explosive device” to its final destination.
The rest of the aviation community won’t.
Those who are legitimately concerned that a fully and properly inflated football might uncontrollably expand at the cabin altitudes maintained in modern aircraft and are likely to explode and do damage to the aircraft and/or injure persons on board will do all that is necessary to deflate said football or have the estranged passenger FedEx or UPS the potential “explosive device” to its final destination.
The rest of the aviation community won’t.
Joined: Dec 1999
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From: UK
rubik101
The ball that blew up in the hold of my 737NG was leather and appeared properly constructed to me!
I'm not making this up, it's the first instance I'm aware of in 16 years flying Boeings but don't tell me it didn't happen.
The properly constructed, hard rubber or leather footballs present no problem whatsoever, even at the normal inflation pressure.
I'm not making this up, it's the first instance I'm aware of in 16 years flying Boeings but don't tell me it didn't happen.
Joined: Jul 2004
Posts: 849
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From: UK
Kill two birds with one stone - use staples to attach the baggage tags to the football before placing it in the hold. AAA which won't fall off those darn tricky plastic surfaces, and instant pressure relief.
Who says Servisair employ clowns?
Who says Servisair employ clowns?
Joined: Aug 2005
Posts: 313
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From: West Africa
Not sure if this adds weight to the debate but I have seen several times packets of chips expand to the point I was very conserned about losing an eye to a thin chip as I opened the packet LOL.
Serious though they expand like crazy at altitude when the cabin is pressuriesed.
weird but true , I wouldnt be surprised if a football would explode if it was pumped hard enough.
Serious though they expand like crazy at altitude when the cabin is pressuriesed.
weird but true , I wouldnt be surprised if a football would explode if it was pumped hard enough.
Joined: Nov 2004
Posts: 264
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From: Sunny East Sussex
A ball is far more likely to explode in an unpressurised cabin at @40000' than in the cabin at cabalt @8000'
So perhaps all balls should be carried in the cabin?
p.s. We don't have this issue in a C-130 as our cabin is our hold!!
So perhaps all balls should be carried in the cabin?
p.s. We don't have this issue in a C-130 as our cabin is our hold!!
Joined: Oct 2002
Posts: 291
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From: Heathrow
Our holds are pressurised - otherwise the floor would have to be extremely stong and therefore heavy.
Some turboprops have unpressurised pods and hold though, but then they don't go tremendously high.
The holds are not usually as well heated as the cabin though.
Some turboprops have unpressurised pods and hold though, but then they don't go tremendously high.
The holds are not usually as well heated as the cabin though.
Joined: Feb 2002
Posts: 178
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From: -
... a pair of Nike Air shoes in the unpressurized hold of a lear 31A did not survive FL430. One of them had burst the shock absorbing air chamber, whilst the other survived. But what good is one shoe?
Regarding footballs in the cabin, leather vs. rubber footbals, one should consider that the rubber footbal being more expandable, it should have pressure differential increase less that the leather version.
On a more important note than 7 or 8 thousand feet, how about a cabin depressurisation at FL410?
Regarding footballs in the cabin, leather vs. rubber footbals, one should consider that the rubber footbal being more expandable, it should have pressure differential increase less that the leather version.
On a more important note than 7 or 8 thousand feet, how about a cabin depressurisation at FL410?
Joined: Jul 2002
Posts: 27
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From: UK
Atctually had this on taxi out last month, crew came up with fully inflated ball saying what do we do with this? After failing miserably to deflate it with anything we could find on the aircraft, ended up stowing it in an empty trolley. To our pleasant surprise it survived the flight. (Think the cabin got to about 7000')
