The bends due to a fast climb

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woxof

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woxof
Was mentioned in an AOPA article recently that a fast climbing unpressurized GA aircraft could result in the Bends or decompression sickness. Anybody ever heard of this happening.
 
woxof said:
Was mentioned in an AOPA article recently that a fast climbing unpressurized GA aircraft could result in the Bends or decompression sickness. Anybody ever heard of this happening.
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Yes, after scuba diving. Don't get in a plane at least 24 hrs after your last dive.
 
Only if you have been diving.
 
The pressure changes for the bends are not fast enough in air as opposed to water. In water the atmospheric pressure in creases by one for every 33 feet of water. Not nearly as fast in air. The second major factor is with diving the pressure goes up as as you go down, which allows more nitrogen to dissolve in your blood. When you come back to normal pressure the decreased pressure at the surface allows nitrogen to bubble out causing the problems. In a plane as you descend the pressure goes up, so the oxygen would be forced back into the blood so no issues.

In theory, if you went very high, very fast it could happen at maximum altitude, but it should not be an issue back at the surface. Coming down would be similar to the treatment for the bends which is a pressure chamber.
 
I've heard that during altitude chamber rides they have the participates breathe 100% oxygen on the way "up" to get rid of the nitrogen.
 
dmspilot said:
I've heard that during altitude chamber rides they have the participates breathe 100% oxygen on the way "up" to get rid of the nitrogen.
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Actually you are on 100% O2 for 30 minutes before the ride up starts to get the nitrogen out of the system. The nitrogen will concentrate in the joints if not purged.

The chamber changes altitude a lot faster than GA aircraft.
Especially during the rapid decompression demonstration.

Now the chambers go to about 25,000ft. We used to go up as high 30,000.
 
As stated above, every 33 feet of water is another atmosphere of pressure. Dive to 16 feet, it's 1-1/2 atmospheres. In air, you must climb to 18,000 feet msl to reach 1/2 atmosphere of pressure. For bends to become a problem requires much more pressure change in a short timeframe. Very few aircraft have a high enough climb rate, maybe some hot military models, certainly nothing with a propellor.
 
I am a PADI Open Water Scuba Instructor and just returned from a week long dive trip where I did twenty dives, all over one hour duration. My dive computer uses a Haldean algorithm for nitrogen build up. While twenty four hours is the conservative and well advised interval between ladt dive and flight in any airplane (my work airplane has a cabin altitude of 8000 feet at 43000 feet) my computer gave me a No Flt time of 15 hours. It would also tell me when I was clean or totally desaturated of excess nitrogen. By using the computer and my knowledge of the recreational dive tables and the physiology of gas laws (an inexact science as each person is different) I could fly before 24 hours but never do. In response to the OP's question, no airplane available to the GA pilot would cause the "Bends" if a diver follows basic rules.
 
You can absolutely get the bends from a rapid decompression of a pressurized cabin at high altitudes, but I don't think there is an airplane out there that can climb fast enough for it to be a factor during normal ops.
 
woxof said:
Was mentioned in an AOPA article recently that a fast climbing unpressurized GA aircraft could result in the Bends or decompression sickness. Anybody ever heard of this happening.
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Oh crap! What does this mean for the future of the zoom climb?? :eek:
 
Last edited:
woxof said:
Was mentioned in an AOPA article recently that a fast climbing unpressurized GA aircraft could result in the Bends or decompression sickness. Anybody ever heard of this happening.
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:rofl::rofl::rofl::lol::lol::lol::lol:
 
drotto said:
The pressure changes for the bends are not fast enough in air as opposed to water. In water the atmospheric pressure in creases by one for every 33 feet of water. Not nearly as fast in air. The second major factor is with diving the pressure goes up as as you go down, which allows more nitrogen to dissolve in your blood. When you come back to normal pressure the decreased pressure at the surface allows nitrogen to bubble out causing the problems. In a plane as you descend the pressure goes up, so the oxygen would be forced back into the blood so no issues.

In theory, if you went very high, very fast it could happen at maximum altitude, but it should not be an issue back at the surface. Coming down would be similar to the treatment for the bends which is a pressure chamber.
Click to expand...

This is the best answer so far, and since someone has already given it, I'll move along to the next thread.
 
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