In a passenger aircraft flying at 10,000m what would happen if a window blew-out?

Question

I know that at this altitude the passenger compartment is pressurised & oxygen is pumped in from compressed storage, and in the films when this happens the pilot does a fast dive & oxygen masks are deployed, but what I want to know is if the depresurization is very rapid, do all the passengers get the Benz or worse (like everyone's eyes & inner-ears burst) as would happen in space?

Answer 1

The first misconception here concerns 'what would happen in space'. Eyes and ears do not burst when the human body is exposed to a space like vacuum, however I will address that point at the end.

I quote:

Consequences of Decompression
A number of practical problems were noted and these do appear to be more serious than the more widely recognised physiological problems due to gas expansion, rapid decompression and high cabin altitudes. Noise in the cockpit caused by wind and the cabin altitude warning horn was noted by a number of crew to be very distracting.
Communications were difficult, both between crew on the flight deck in the event of a windshield loss, and between flight crew with cabin crew and cabin crew with passengers.

Physical hazards such as noise, extraction, debris and cooling are well recognised, but in most decompressions there is very little risk of mechanical injury.

The most important physiological hazard is hypoxia, and although gas expansion will occur, injury experience even in the most extreme rapid decompressions are either blast
injuries or otic barotrauma due to subsequent rapid descent. The theoretical risks of intrapulmonary gas expansion during the rapid decompression itself appear to be well
addressed by aircraft design. Other problems at altitude include the risk of hypothermia due to low ambient air temperatures as well as the expansion of gas in the cabin itself. There have been no reports of decompression illness resulting from rapid decompression although there is a theoretical risk if the cabin altitude exceed 18,000 feet.

The position of any structural defect will make a significant difference to the cabin altitude; where the structural failure such as a windscreen is located at the front of the aircraft there may be a significant "ram air" effect, whereas it if is on the side or rear of the aircraft there may well be a suction effect due to Venturi forces acting around the defect. This can make a difference to between 2.5 and 1 lb/sq inch to the final cabin altitude. The continued operation of pressurisation packs can also contribute to significantly lower final cabin altitudes following a rapid decompression by as much as
1,000 feet pressure altitude.

Returning to the Space vacuum issue -

From the now extinct page http://medlib/jsc.nasa.gov/int...

How long can a human live unprotected in space?

If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.

Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.

You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn.

At NASA's Manned Spacecraft Center (now renamed Johnson Space Center) we had a test subject accidentally exposed to a near vacuum (less than 1 psi) in an incident involving a leaking space suit in a vacuum chamber back in '65. He remained conscious for about 14 seconds, which is about the time it takes for O2 deprived blood to go from the lungs to the brain. The suit probably did not reach a hard vacuum, and we began repressurizing the chamber within 15 seconds. The subject regained consciousness at around 15,000 feet equivalent altitude. The subject later reported that he could feel and hear the air leaking out, and his last conscious memory was of the water on his tongue beginning to boil.

Aviation Week and Space Technology (02/13/95) printed a letter by Leonard Gordon which reported another vacuum-packed anecdote:

"The experiment of exposing an unpressurized hand to near vacuum for a significant time while the pilot went about his business occurred in real life on Aug. 16, 1960. Joe Kittinger, during his ascent to 102,800 ft (19.5 miles) in an open gondola, lost pressurization of his right hand. He decided to continue the mission, and the hand became painful and useless as you would expect. However, once back to lower altitudes following his record-breaking parachute jump, the hand returned to normal."

References:

Frequently Asked Questions on sci.space.*/sci.astro

The Effect on the Chimpanzee of Rapid Decompression to a Near Vacuum, Alfred G. Koestler ed., NASA CR-329 (Nov 1965).

Experimental Animal Decompression to a Near Vacuum Environment, R.W. Bancroft, J.E. Dunn, eds, Report SAM-TR-65-48 (June 1965), USAF School of Aerospace Medicine, Brooks AFB, Texas.

Survival Under Near-Vacuum Conditions in the article "Barometric Pressure," by C.E. Billings, Chapter 1 of Bioastronautics Data Book, Second edition, NASA SP-3006, edited by James F. Parker Jr. and Vita R. West, 1973.

Personal communication, James Skipper, NASA/JSC Crew Systems Division, December 14, 1994.

Henry Spencer wrote the following for the sci.space FAQ:

You would probably pass out in around 15 seconds because your lungs are now exchanging oxygen out of the blood. The reason that a human does not burst is that our skin has some strength. For instance compressed oxygen in a steel tank may be at several hundreds times the pressure of the air outside and the strength of the steel keeps the cylinder from breaking. Although our skin is not steel, it still is strong enough to keep our bodies from bursting in space.

Also, the vapor pressure of water at 37 C is 47 mm Hg. As long as you keep your blood-pressure above that (which you will unless you go deep into shock) your blood will not boil. My guess is that the body seems to regulate blood pressure as a gauge, rather than absolute pressure (e.g. your blood vessels don't collapse when you dive 10 feet into a pool).

The saliva on your tongue might boil, however.

For more information and references, see http://www.sff.net/people/geoffrey.landi...

Source(s):
http://imagine.gsfc.nasa.gov/docs/ask_as...

Answer 2

The dangers are hypoxia (lack of oxygen due to thin air) and cold. You might get sucked out the window if you're unlucky, but if you hold tight, once the pressure equalizes there'll be no more sucking (so to speak).

The rule of thumb in flying is that being exposed to thin air above 10,000 feet will threaten hypoxia. That's why the first emergency procedure is to dive to lower altitude. So at 10,000 m (33,000 feet), which is higher than Mt. Everest, yes people would start acting weird and then pass out from lack of O2 pretty quick. Then again you can hold your breath for a minute or two, right, so it's not exactly instantaneous. Of course the O2 masks should pop out in a passenger plane. But probably nothing too physiologically damaging will happen assuming you get to breathing oxygen reasonably soon.

Now the cold is another issue. The air temp drops 4 degrees F for each 1000 feet of higher altitude. So at that high, the temp will be like 130 degrees F below surface temp. Pretty damn cold once the heated cabin air blows out. Not sure exactly how that would affect you in a short time period -- it would suck, but if the pilots are responding and lowering altitude I reckon you won't flash-freeze to death.

Answer 3

The Bends is actually called decompression sickness It is something that you get when SCUBA diving and is a result of Nitrogen collecting in your joints while your body is under more pressure then normal, not less. If you come up too quickly and don't let the gas breakdown it is very painful. See the link.

No to the second part as well, most peoples ears and eyes will not bleed, if the plane doesn't descend below 10,000ft quickly people will pass out due to lack of oxygen. Hence the need for the oxygen masks.

Answer 4

There would be a rapid decompression, the oxygen masks whould deploy, no one would be sucked out of the plane. It would get really windy and unpleasent, the pilot would desent but not like the movies. The flight attendants would put on supplemental oxygen (portable) and help the passengers eith their masks. No one would get the bends, rather the opposite hypoxia or oxygen deprivation. The pilots have masks with in reach that are forced Oxygen. They are kind of neat, and help with hang-overs. All in all it wouldn't be pleasent but not the end of the world. I used to fly with United for a year. We had to study and practice in training and recurrent. Hope that helps...

Brian

Answer 5

Yes there is a chance that nitrogen would come out solution in their blood which is one of the reasons the pilot would do a dive. As far as I know, there are no eye and inner ear popping going on, but the difference in pressure between the inside and outside of the craft may cause some objects to get sucked out. Of course this would happen within the first few seconds because the pressure would equilibrate rapidly.

Answer 6

The thing you're thinking of is the bends, not the Benz, which is a car company :)

The bends, or nitrogen narcosis, is caused when a rapid depressurisation causes bubbles of nitrogen to form in the blood, but only when the body has been at much higher pressure than you would get on an aeroplane, such as under water.

As for on the plane, you'd probably not have too much trouble. It would be worse at cruising altitude, which is thirty-odd thousand feet.

Answer 7

Interesting point...I have never heard of someone getting the Bends. I guess it's possible. The pilot dives in order to get below the altitude threshold to reduce the depressurization. It doesn't take long for the air to get sucked out at 30,000 ft., and there would very likely be major medical issues. In real life, planes that depressurize don't usually make it back. The DC-10 had major issues with cargo doors, and metal fatigue caused many near crashes.

Answer 8

Decompression wouldn't happen as quickly as it is shown in the movies. The compression ratio at that height would be about 10:1. The passengers would have about 1 min before they passed out unless they got to oxygen. If the pilots are smart, they would set the autopilot to level out at 3000m before/if they passout.

Answer 9

above 10000 feet theres not enough oxygen, so you go into cyanosis very quickly... and die.

at 35000 feet teh pressure differential will suck you and everything else out of the window, untill the pilot can reduce height to under 10 thousand feet... and in the 20000 feet decent, youll either freeze, or asphyxiate... or both.

the bends (Benz invented the combustion engine) is caused by compressed nitrogen expanding as the external pressure is reduced.

youve seen arnie on mars in total recall... well after they blow the dome... thats a fair example of what will happen...

and 10 thousand metres is almost 35000 feet, and 20000 feet is five miles...

Answer 10

No, the depressurization would not be as quick as if it happened in space. You would have a few minutes to get your mask on and your ears might pop but nothing more serious than that. There is still some air at 10,000 meters so it's not like a vacuum.

Answer 11

The rapid decscent is a much down to the temperature as anything else - at that height air temp is about -35C. This happened to Payne Stewart the golfer a few years ago - the 'plane depressurised, but carried on flying on the auto pilot but it was thought that the passengers and crew had frozen to death rather than suffocating. They had to bring the plane down with military jets to avoid further loss of lie if I remember