haz777
Topic Author
Posts: 4
Joined: Tue Oct 23, 2018 1:33 pm

Explosive decompression question

Tue Oct 23, 2018 1:44 pm

Hi, I have a question regarding explosive decompression, particularly in cases following an onboard explosion. How can explosive decompression rip an aircraft apart after, for example, a bomb detonates? Does it tear of the fuselage section's bolts that hold it together? I have trouble imagining just a small hole being able to take down an airliner.

I know there have been explosions at low altitudes and the aircraft has remained structurally intact and I know there is Phillipine Airlines 434, but in that case there was no damage to the hull. My second question which I am dying to know is has there ever been a case when an aircraft has survived a high altitude bombing (28,000 + feet) and also sustained damage to the fuselage without disintegrating in mid air? Or a 10 inch hole at high altitude seal an aircraft's fate. I have tried searching far and wide but couldn't find what I was looking for so thought I'd ask on here since it's bugging me

Many thanks

Harry
 
GalaxyFlyer
Posts: 1502
Joined: Fri Jan 01, 2016 4:44 am

Re: Explosive decompression question

Tue Oct 23, 2018 3:04 pm

Depends greatly on where the explosive is located on detonation, see PAA 103 where are rather small charge did enough skin damage to let the 340 knot slipstream do the rest.

A bomb went off in an airliner in the early 60s, B707 IIRC, the plane survived the explosion, but in the ensuing haste to descend came apart in the teens as the IAS built up. Now, if damage cannot be confirmed, emergency descent is done at the indicated airspeed at the time of the explosion or structural damage.

GF
 
BoeingGuy
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Joined: Fri Dec 10, 2010 6:01 pm

Re: Explosive decompression question

Tue Oct 23, 2018 4:12 pm

GalaxyFlyer wrote:
Now, if damage cannot be confirmed, emergency descent is done at the indicated airspeed at the time of the explosion or structural damage.

GF


To be specific, an excerpt from the Boeing QRH procedure for CABIN ALTITUDE (decompression) is:


Without delay, descend to the lowest safe altitude or 10,000 feet, whichever is higher.

To descend:

•Move the thrust levers to idle
•Extend the speedbrakes
•If structural integrity is in doubt, limit airspeed and avoid high maneuvering loads
•Descend at Vmo/Mmo


So there is guidance on possibly limiting airspeed if structural integrity is in question.
 
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Balerit
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Re: Explosive decompression question

Tue Oct 23, 2018 6:59 pm

Aircraft structure is designed to carry the load should something small pierce the pressure hull. What a bomb does is damage this redundancy causing several stringers or frames to give way. Just remember that a fuselage under pressure is like a balloon waiting to pop. Structural failure, ie metal fatigue causes the exact same result. There are some who believe that all the B747 so called bombings were in actual fact section 41 structural failure.

There was recently an A320 that suffered a bomb blast and made it safely back to the ground, think it was Air Egypt or something like that. The bomber was the only casualty.
Licensed Aircraft Maintenance Engineer (retired).
 
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litz
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Re: Explosive decompression question

Tue Oct 23, 2018 7:36 pm

There have been a few aircraft that suffered non-explosives related explosive decompression, too ... Aloha and UA (737 and 747, respectively) being the most newsworthy due to the extreme fuselage damage.

There have also been a couple of SWA 737s that had much smaller "blowouts" as well.
 
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Francoflier
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Joined: Wed Oct 31, 2001 12:27 pm

Re: Explosive decompression question

Tue Oct 23, 2018 11:58 pm

Maybe it's paranoia talking here, but does a very specific question about bombs and airplanes from a new user whose very first post it is seem suspicious to anyone else?
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
haz777
Topic Author
Posts: 4
Joined: Tue Oct 23, 2018 1:33 pm

Re: Explosive decompression question

Wed Oct 24, 2018 12:21 am

Thanks for your answers guys, the incentive for my question was Pan Am 103 and the recent Metrojet bombing. I am trying to get my head around these disasters as it seems so horrific that such a strong jet can break apart in mid air and kill so many people. If only we could find a way to prevent these disgraceful events. Hopefully airlines will adopt the recently developed kevlar bomb bag. Thanks for your answers BoeingGuy, GalaxyFlyer and Balerit, very interesting responses. Btw Balerit, that was a Daallo airlines a321 on the way to Djibouti, I was impressed by the aircraft's structure but the captain said if it had happened at cruise altitude the jet could have crashed. Is there any chance that jet could have survived a bomb at cruise altitude considering it tore a hole in the cabin? I am hoping it could tbh thats why I'm kind of asking this question. Is there any chance a jet can survive if the hull is pierced at high altitude, I want to believe the aircraft structure can take such a load but tbh it is the first thing on my mind when I fly.
 
haz777
Topic Author
Posts: 4
Joined: Tue Oct 23, 2018 1:33 pm

Re: Explosive decompression question

Wed Oct 24, 2018 12:27 am

Francoflier,

I created this account because I often read this site as well as enjoy its many helpful and informative posts, and want reassurance that the next time I fly there is a chance that if some deranged person or terrorist decides to put a bomb in the cargo hold that there is at least a tiny chance of survival. I am afraid I cannot understand that mindset and I do not wish to even be spoken about in the same sentence as those animals
 
GalaxyFlyer
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Re: Explosive decompression question

Wed Oct 24, 2018 2:11 am

Yes, an explosion could be survivable, but a lot of luck is involved. The 707 might have survived had the crew been trained as we are today, as opposed to reverting to rapid descent training. A C-141 many moons ago had an aft door complex let go, as close to a bomb as possible to recreate. The crew, save the co-pilot lost consciousness, but the co-pilot reacted corrected and saved it.

GF
 
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zeke
Posts: 12782
Joined: Thu Dec 14, 2006 1:42 pm

Re: Explosive decompression question

Wed Oct 24, 2018 6:08 am

haz777 wrote:
Hi, I have a question regarding explosive decompression, particularly in cases following an onboard explosion.


Sounds like a bad case of Delhi belly, it is sure to cause an explosion and rip something apart. Frequently causes discomfort to other passengers.

:roll:
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Balerit
Posts: 582
Joined: Sun Aug 23, 2015 9:14 am

Re: Explosive decompression question

Fri Nov 02, 2018 11:23 pm

Have look here at what a fuselage looks like showing the stringers and frames and in the Daallo case only a few stringers were damaged and none of the frames:
[url]
http://www.zoombd24.com//wp-content/upl ... ctures.png[/url]
Licensed Aircraft Maintenance Engineer (retired).
 
strfyr51
Posts: 3044
Joined: Tue Apr 10, 2012 5:04 pm

Re: Explosive decompression question

Sat Nov 03, 2018 6:59 pm

Francoflier wrote:
Maybe it's paranoia talking here, but does a very specific question about bombs and airplanes from a new user whose very first post it is seem suspicious to anyone else?

Actually?? Yes! Now that you mention it.
 
strfyr51
Posts: 3044
Joined: Tue Apr 10, 2012 5:04 pm

Re: Explosive decompression question

Sat Nov 03, 2018 7:11 pm

haz777 wrote:
Thanks for your answers guys, the incentive for my question was Pan Am 103 and the recent Metrojet bombing. I am trying to get my head around these disasters as it seems so horrific that such a strong jet can break apart in mid air and kill so many people. If only we could find a way to prevent these disgraceful events. Hopefully airlines will adopt the recently developed kevlar bomb bag. Thanks for your answers BoeingGuy, GalaxyFlyer and Balerit, very interesting responses. Btw Balerit, that was a Daallo airlines a321 on the way to Djibouti, I was impressed by the aircraft's structure but the captain said if it had happened at cruise altitude the jet could have crashed. Is there any chance that jet could have survived a bomb at cruise altitude considering it tore a hole in the cabin? I am hoping it could tbh thats why I'm kind of asking this question. Is there any chance a jet can survive if the hull is pierced at high altitude, I want to believe the aircraft structure can take such a load but tbh it is the first thing on my mind when I fly.

At Altitude a hole in the fuselage depending on the size is not fatal. However? it depends on Where the Hole is and the size ot it that makes the difference. I've seen 3 in my lifetime up close and personal..
Nove of the 3 breached the main longitudinal spars. but they did damage circumfrentail stringers. so the airplane didn't come apart.. I ssrillhold the Theory that TWA's center fuel tank hadn't a damn thing to DO with that crash. I still submit that a Navy Missle went through that fuselage and that WHOLE deal was a cover-up. all of this Center fuel tank Inerting stuff is a bunch of Hooie !! Tea was almost Broke and after that incident bought a bunch of Brand NEW B757's Are you kidding me??
 
Yikes!
Posts: 286
Joined: Sat Oct 13, 2001 4:51 pm

Re: Explosive decompression question

Mon Nov 12, 2018 5:08 am

Francoflier wrote:
Maybe it's paranoia talking here, but does a very specific question about bombs and airplanes from a new user whose very first post it is seem suspicious to anyone else?


This is exactly the type of topic that should not be discussed nor commented about here.

Have posters learned nothing since prior to 9-11 where some believe THIS FORUM provided information to the 9-11 hijackers in advance of their heinous actions?
 
WKTaylor
Posts: 31
Joined: Mon Jul 25, 2016 9:36 pm

Re: Explosive decompression question

Mon Nov 12, 2018 5:46 pm

No much 'out-there', RE sudden aircraft decompression: design philosophy/info/etc.

Interesting engineering perspective in 'SAE AIR5661 Compartment Decompression Analysis'
 
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CALTECH
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Re: Explosive decompression question

Wed Nov 14, 2018 4:56 pm

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