Hello.
In many movies (such as Drop Zone or Executive Decision among others), we see a typical scene in which an airliner flying at its cruising altittude and speed suddenly suffers an explosive decompression and one or more rows of seats are blown out of the plane. In real life, seats are fixed to the cabin floor, so my doubt is: if we fly an airliner at its regular altitute and speed and suddenly we make a big hole in the fuselage but the cabin floor is NOT damaged, will seats next to that hole resist the strong forces of the air rushing out? Also, if seats do resist and stay in their places, and they have passengers sitting in them with their belts fastened, will the belts keep those passengers in their seats inside the plane?
I’m not an aviation expert, but I have read of a few accidents involving decompressions and I find it hard to answer my question. For example, we have United Airlines flight 811 in which several rows of seats were blown out, but in this case the cabin floor itself was damaged and partially collapsed, so it seems obvious to me that some seats had to be ejected from the plane. And even so, all other seats (included some that were really close to the very big hole) stayed in their places. We also have the famous Uruguayan Air Force flight 571 which crashed in the Andes in 1972, in which not only were some seats blown out when the plane lost its tail, but also the remaining ones were ejected forwards when the plane abruptly stopped against the snow, but in this case the plane suffered such a structural damage that it’s logical that seats were torn from their fixations. Also I guess (although I can’t confirm it) that seats of that old prop plane weren’t as strong as those found in modern jet airliners.
On the other hand, we have that Aloha Airlines flight 243 which is probably one of the most dramatic explosive decompressions in aviation’s History, yet all seats and passengers sitting in them survived, with the only fatality being a flight attendant who wasn’t secured when the decompression ocurred.
There’s also a MuthBusters episody in which they pick an old airliner from a junkyard, sit a dummy in one window seat, pressurize the plane with a big compressor to simulate the pressure differential between the inside and the outside of the plane, and then they perform several decompressions, with the dummy staying in its place in all cases (although taking some damage). However, this simulation fails to take into account the great speed of the plane: just drive a four door car at 100 km/h (60 mph) with the four windows fully opened and you will have a strong turbulence inside the car. Now, imagine a plane flying at 8 times that speed with a hole several times bigger than the combined size of the four car windows. Also, the force exerted by a fluid current is proportional to the square of its velocity, which means that if you multiply the speed by 8, the force will be… 64 times stronger!!! Well, it’s also true that at an altittude of 10k meters (32800 feet) air density is approximately 1/3 of that at sea level, but still the force would be about 20 times stronger. Is it possible that seats resist such a rush of air? Airliner seats are bigger than those of cars, therefore they create a greater aerodynamic resistance, and that means a greater force pushing them.
Finally, I saw The Plane Crash documentary in which a team purposely crash landed an airliner and a few seats were ejected from the plane (in this case, no decompression was involved), but once again the plane itself took a great structural damage.
So what are your opinions?
By: Arabella-Cox - 21st April 2016 at 10:31
8 PSI is the differential, i.e. the difference between the inside and the outside. So the actual pressure inside the cabin is a bit more than 8 PSI. (8 plus whatever the environmental pressure at the airplane’s altitude is) Sea level pressure is around 15 PSI. At 40,000′ the cabin altitude is between 6,000′ (B787) and 8,500′ (older types).
Hope this helps.
By: hampden98 - 20th April 2016 at 18:53
What was interesting in the Myth Busters test was that the cabin was pressurised to 8psi.
Apparently this simulates 40’000 feet.
I always thought the pressure would be more?
By: Gryphus One - 7th April 2016 at 02:16
Mythbusters tested the Hollywood `bullet through the window passengers sucked out` scenario (by pressurizing an airliner and shooting a bullet through a window) and determined that this does not happen.
Yeah I saw that video, however their experiment, although does take into account the pressure differential between the inside and the outside of the plane, fails to simulate the great speed that airliners fly at, which I guess is another serious factor to take into consideration.
On 24 Feb 1989, United Airlines flight 811 a Boeing 747-100 experienced an explosive decompression as it was climbing between 22,000 and 23,000 feet after taking off from Honolulu, Hawaii, en route to Auckland and Sydney. The airplane made a successful emergency landing at Honolulu and the occupants evacuated the airplane. Examination of the airplane revealed that the forward lower lobe cargo door had separated in flight and had caused extensive damage to the fuselage and cabin structure adjacent to the door. Nine of the passengers had been ejected from the airplane and lost at sea.
https://aviation-safety.net/database/record.php?id=19890224-0
Yeah, I mentioned this accident myself in the first post, but in this case the cabin floor partially collapsed, and seats are attached to it. What I’m wondering is what would happen if there was a massive decompression but without the cabin floor being damaged.
By: Dragonflyer - 6th April 2016 at 22:41
Thank you for sharing this first hand experience. Interestingly, the level of available mobility with the suit inflated was praised in the ’50’s 😉
Very different pressure suit in the 50’s. That was the old skin-tight Partial Pressure suit. It was replaced in the U-2R with the full pressure suit…much more comfortable deflated.
By: TomcatViP - 6th April 2016 at 20:37
Thank you for sharing this first hand experience. Interestingly, the level of available mobility with the suit inflated was praised in the ’50’s 😉
For the Concord flying at 80000 ft Hampden98, please see wiki extract below:
18,300 metres
Concorde had a maximum cruise altitude of 18,300 metres (60,039 ft) and an average cruise speed of Mach 2.02, about 1155 knots (2140 km/h or 1334 mph), more than twice the speed of conventional aircraft.
By: Dragonflyer - 6th April 2016 at 16:56
Yes, U-2 pilots wear a pressure suit, but not really because of this scenario. Our usual issues were related to loss of cockpit pressure due to a damaged seal on the canopy or equipment bay (E-Bay) hatch which lowered cockpit pressure slowly to moderately fast but not “explosively”. Even if the canopy was suddenly lost, I don’t think it would be much of a problem in this respect, unless the canopy hit the tail and forced an ejection. In my day the cockpit was pressurized to about 30,000 feet (9000 meters) so the volume of air escaping was significantly less (therefore less dense) than an airliner. Also, we were very securely strapped into the ejection seat which was pretty firmly integrated into the cockpit structure. The cockpit pressure altitude has been lowered (actual pressure raised) recently to help prevent bends/CNS issues but I still don’t think inadvertently being tossed out is an issue for U-2 pilots.
BTW, I have lost pressure on a flight, but it was more of a nuisance event than a real concern (it’s like being inside the Pillsbury doughboy when the suit inflates…pretty limited mobility until you descend).
By: Arabella-Cox - 6th April 2016 at 12:43
On 24 Feb 1989, United Airlines flight 811 a Boeing 747-100 experienced an explosive decompression as it was climbing between 22,000 and 23,000 feet after taking off from Honolulu, Hawaii, en route to Auckland and Sydney. The airplane made a successful emergency landing at Honolulu and the occupants evacuated the airplane. Examination of the airplane revealed that the forward lower lobe cargo door had separated in flight and had caused extensive damage to the fuselage and cabin structure adjacent to the door. Nine of the passengers had been ejected from the airplane and lost at sea.
https://aviation-safety.net/database/record.php?id=19890224-0
By: Gryphus One - 6th April 2016 at 02:11
The Turkish DC10 heading for London Heathrow crashed near Paris in 1974, cargo door not shut properly, resulting in an explosive decompression, farmers came across 6 passengers still strapped to their seats in fields 9 miles away from the crash site. This crash was a watershed moment for the aviation industry as it was the first wide body crash with mass fatalities, 346 people in total died. Sad day for all.
https://en.m.wikipedia.org/wiki/Turkish_Airlines_Flight_981
Yeah but in this accident a part of the cabin floor collapsed, that’s why some seats attached to it were blown out.
By: hampden98 - 3rd April 2016 at 10:13
I think we have to differentiate between rapid decompression and rapid decompression resulting in the loss of control and eventual break up of the aircraft.
Mythbusters tested the Hollywood `bullet through the window passengers sucked out` scenario (by pressurizing an airliner and shooting a bullet through a window) and determined that this does not happen.
There is a rapid blast of air and a passenger next to the breach may move but there is not enough force to suck you or anything else out of the aircraft.
Perhaps if the hole was big enougth and you were not strapped down you may be sicked out by the slipstream.
A cargo door blowing out most likely will cause a loss of control, break up and lead to passengers thrown out in seats like at Lockerbie.
Something that has always interested me is what would have happened to Concorde at 80’000 feet with a rapid decomp?
U2 pilots wear Spacesuits for a reason.
By: FLY.BUY - 2nd April 2016 at 22:17
The Turkish DC10 heading for London Heathrow crashed near Paris in 1974, cargo door not shut properly, resulting in an explosive decompression, farmers came across 6 passengers still strapped to their seats in fields 9 miles away from the crash site. This crash was a watershed moment for the aviation industry as it was the first wide body crash with mass fatalities, 346 people in total died. Sad day for all.
https://en.m.wikipedia.org/wiki/Turkish_Airlines_Flight_981
Sign In
March 10, 2016 at 3:02 am