Since it is an Airbus, there is a computer glitch.
First, the cabin is fully depressurized. Your eardrums burst.
Fortunately, the wimpy oxygen mask pops down. You start inhaling O2, lets say for the sake of the arguement that you get an-impossible-with-that-rig 100%.
Then, the pilot announces that the computer prevents the plane from descending and you stuck at 38,000 ft over the Pacific Ocean, but there is enough fuel and oxygen for 6hrs by which time the problem will be fixed.
Based upon a quick Google search, I believe the answer is yes, according to this article in The Internet Journal of Pulmonary Medicine. 38,000' appears to the maximum altitude allowed for commercial airliners.
..."When one is breathing pure O2 at 33,700 ft, the partial pressure of O2 in the alveoli is the same as the pressure at SL when breathing air. Above 34,000 ft, the partial pressure of O2 in the lungs begins to fall below the pressure at SL, even though 100 % O2 is breathed. At altitudes greater than 40,000 ft, the partial pressure of O2 decreases rapidly and falls below the limit that maintains the body in a physiologically safe condition."
..."Cabin pressurization in modern aircraft ensures that the effective altitude to which occupants are exposed is much lower than that at which the aircraft is flying. Commercial aircraft are not pressurized to sea level but to a relatively modest intermediate cabin altitude. This allows the aircraft to fly at much higher altitudes, which is fuel efficient for jet engines and more comfortable since it avoids much turbulence. Aircraft cabin altitude can thus approach 2438 m (8000 ft) while the aircraft is flying at 11,582 m (38,000 ft). Therefore, a pressure differential exists across the cabin wall, commonly of up to 9 pounds per square inch (psi). International aviation regulations stipulate that, at a plane's maximum cruising altitude, the cabin pressure should not exceed 2438 m (8000 ft). This may be exceeded in emergencies. (5)
In the event of failure of the cabin pressurization system at high altitude, all occupants would require supplemental oxygen to prevent an unacceptable degree of hypoxemia. Commercial aircraft are thus equipped with an emergency oxygen system for passengers, demonstrated before each flight in accordance with civil aviation regulations. However, some passengers with impaired respiratory function may be unusually susceptible to the effects of ascent even to normal cabin altitudes. (6)"
By the time normal cabin pressure is restored in 6 hours, I would expect to see many passengers in varying degrees of respiratory distress.
Since it is an Airbus, there is a computer glitch.
The way I understand this episode is that the gear was down, the a/c was less than 100' AGL and so the computer "knew" a landing was required... And, as computers are prone to do - did it.
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII
Hmmmmm . . . six hours in a jetliner over the Pacific, at 38K', with burst eardrums, breathing 100% O2. Assuming the plane doesn't crash or the burst eardrums don't have some serious de-pressurizing imbalance on the brain that leads to immediate HACE and a quick trip to the pearly gates.
My first inclination is a highly confident "maybe". That's 9000 feet higher than Everest, where many well-acclimated people have passed away quite rapidly, especially in that "Death Zone" above 26,000 feet. In six hours under those circumstances, I'm pretty sure some would die and some would live - I just have no clue about the percentages. I also recall that even breathing 100% Os at extremely high elevation, the effective altitude effect on the body doesn't really drop that much (at least as far as frostbite risk).
Since your question was "can you live", not "would you live", I'll go with Kevin and say "yes". But not for long.
"Simply increasing the fractional concentration of oxygen is totally inadequate at pressure altitudes above 40,000. Measured aveolar oxygen pressures in subjects breathing 100% oxygen are only about 34Hg at 45,000 feet You would die of hypoxia breathing 100% oxygen at a pressure altitude of 45,000 feet. To survive you would need to decrease pressure altitude through pressurization or breath positive pressure oxygen."
you guys are good, much better than some of the other high altitude respondents we see here and there.
I purposefully made it vague with 38,000 ft the top of commercial's ceiling, and the hint about assuming 100% O2 from the wimpy mask - not possible in real world.
They all would die.
The inefficiency of ill-fitting loose masks and panic results in far less than 100% intake. Above 31,000 ft, Air Force recommends 100% O2 and to use pressure masks (those thick, strapped-tight black rubber face-imprinting things) and requires it above 40,000 ft.
100% O2 alone will not save you, you need the pressure.
Harvey
PS Charlie Houston of K2 fame and mountaineering medicine did two studies called Operation Everest. You know, stuff like putting pilots in hypobaric chambers and watching them pass out in 20 seconds.
wagga I immediately thought of the Payne Steward episode where they all were almost instantaneously incapacitated and unable to have time to put on their oxygen masks.One assumes the pilots were wearing their masks or had them readily at hand but as Harvey points out it is the pressure and not the oxygen.It is similar to a diver assending too quickly from depth.Boyles Law I seem to recall.
As I remember, the Payne Steward incident was a was thought to be a slow leak where they didn't have a chance to realize that there was a problem, they just passed out.
This looks interesting (although much of it is too technical for me), and also seems to indicate that 38,000' is not the highest allowable flight level (were you just arbitrarily throwing out that figure?). It looks like it was 40,000' (at the time of the writing of this piece), with even higher levels envisioned with increasing technological advancement. If memory serves, I think I also recall being in a commercial airliner at either 39,000' and/or 41,000' in the past 5-10 years.
CaT
If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)
yeah, I just threw the 38,000 as an approximation. If the plane is fuel/passenger heavy or at polar latitudes where the air is thinner it might not get that high. Just fun stuff to ponder.
"Simply increasing the fractional concentration of oxygen is totally inadequate at pressure altitudes above 40,000. Measured aveolar oxygen pressures in subjects breathing 100% oxygen are only about 34Hg at 45,000 feet You would die of hypoxia breathing 100% oxygen at a pressure altitude of 45,000 feet. To survive you would need to decrease pressure altitude through pressurization or breath positive pressure oxygen." ... Got this info from this site - www.dr-amy.com/rich/oxygen ...
In a pressure-demand system, oxygen in the mask is above ambient pressure, permitting breathing above 34000 feet. Because the pressure inside the mask is greater than the pressure around the user's torso, inhalation is easy, but exhalation requires more effort. Aviators are trained in pressure-demand breathing in altitude chambers. Because they seal tightly, pressure-demand-type oxygen masks are also used in hyperbaric oxygen chambers and for oxygen breathing research projects with standard oxygen regulators.
Interesting physics. We think about the act ( and need) of inhaling the oxygen under pressure, but exhaling is a problem with using only a pressure demand system. Eventually, one must use a full suit so the the whole body is pressurized (like in the picture in that link of the late- Steve Fossett and Mr. E. in New Zealand). This is getting way out of my league. Thanks, Harvey
Since moving to Inyokern I've learned that it's an ideal location for high-altitude gliding, in part because of the "Sierra Wave". A friend of ours just passed away, and you can read about his amazing life here.
Here's an excerpt from Owl's obit - "Al achieved his dream of learning to fly shortly after he arrived at China Lake in 1952. Over the years, he owned many airplanes, alone and in partnership. He became a highly skilled pilot and one of the area's best instructors. Eventually he earned many pilot ratings, including airplane, instrument, glider, ATP (Airline Transport Pilot), seaplane, and helicopter. In the mid-'50s he was attracted to soaring and checked out in sailplanes at the famed soaring site of El Mirage in the California desert. He became very interested in the Sierra Wave phenomenon which had been discovered in the 1950's and explored the wave on many flights with his Cessna 170. He achieved the Soaring Society altitude gain goals of 1,000 meters (3281 feet) and 3,000 meters (9842 feet) by shutting down the engine in the airplane and soaring it like a glider. On his best flight, he soared the 170 from 6,000 feet to 33,000 feet, but the recording barograph system failed so that achievement was never recognized. On that flight the battery died from the cold at altitude, and he landed dead stick at the old Davis Airport after dark in high winds, with no radio or lights, an amazing accomplishment. (emphasis mine)"
