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Barotrauma is damage of lungs by air overpressure and may occur at overpressure as low as 30 kPa (4 psi). Overpressure in most aircraft is about double that value. So is it possible to suffer barotrauma when rapid1 decompression occurs? In an airliner or only in small airplane? And did it happen?

1If the decompression is explosive and the aircraft falls apart almost certainly, but it does not matter as all occupants will be dead either way. Only consider the case when the aircraft remains controllable.

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    $\begingroup$ if you are holding your breath, probably $\endgroup$ – ratchet freak Oct 15 '14 at 13:48
  • $\begingroup$ I think you may be overestimating the power of "explosive decompression". Commercial aircraft pressurize the cabin to about 12 PSI. This is an extremely wimpy amount of pressure. A balloon is 16 PSI. A can of soda about 35. Letting the air out of a balloon would be a more dramatic event than a plane decompressing. $\endgroup$ – Tyler Durden Oct 23 '17 at 19:23
  • $\begingroup$ @TylerDurden, no, you are overestimating the durability of human lungs. If you had air from a 16 psi-balloon forced down your windpipe, it would tear your lungs to shreds. By the way, 12 psi is a bit too high even for absolute cabin pressure. $\endgroup$ – Jan Hudec Oct 24 '17 at 14:37
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Briefly: yes, it's possible (but very unlikely); small pressurized aircraft are the more likely scenario; maybe it has happened but if so it's very rare.

According to the FAA's AC on Aircraft Operations at Altitudes Above 25,000 Feet Mean Sea Level or Mach Numbers Greater Than .75 it's possible and more likely to happen in a smaller pressurized aircraft:

(a) Explosive Decompression. A change in cabin pressure faster than the lungs can decompress. Most authorities consider any decompression that occurs in less than 0.5 seconds as explosive and potentially dangerous. This type of decompression is more likely to occur in small volume pressurized aircraft than in large pressurized aircraft and often results in lung damage. [...]

(b) Rapid Decompression. A change in cabin pressure where the lungs can decompress faster than the cabin. The risk of lung damage is significantly lower in this decompression compared to an explosive decompression.

Unfortunately they don't cite any statistics or source for the statement "often results in lung damage" so it isn't clear when it has actually happened. Other sources suggest that it's very rare, for example Beyond the Black Box: The Forensics of Airplane Crashes says this:

The Air Force reports no serious injuries resulting from rapid decompression with open airways, even while wearing an oxygen mask. However, disastrous, even fatal consequences can result if the breath is forcibly held with the lungs full of air. [...]

Lung damage is considered nearly impossible in a commercial aircraft because of the large volume of air inside the plane. [...] Even Aloha Flight 243 [...] did not decompress fast enough to cause internal injuries.

In other words, it's not going to happen unless you hold your breath, but another source says that you won't be able to do that anyway:

I've had pilots tell me they would be able to hold their breath [in order to extend the time of useful consciousness]. That won't happen. First of all, the surprise of the event will override any defensive measure you may have thought you could put into place. Secondly, the rapid change in pressure differential will make it impossible to hold your breath. (Remember, we can be talking about a pressure differential of 8.8 PSI. Let's put these pressure differentials into perspective. A differential of 8.8 PSI is 1267 pounds per square foot.

I think the surprise is a key point here: the flight or fight response increases your breathing rate so even if it were physically possible to hold your breath it's extremely unlikely that you would do so.

Interestingly, Google finds numerous sources that claim lung injuries are commonly caused by aircraft decompression, but I couldn't find any source that mentioned a specific incident or even any statistics on it. I did find one book that studied 47 incidents of aircraft decompression but there was only one single barotrauma event among them and it affected the ears, not the lungs.

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  • $\begingroup$ Great answer, thanks. Apparently divers can suffer plumonary barotrauma by holding their breath and raising, so scuba diving trainees are explicitly warned not to forget to start breathing again after listening for incoming ships. So the last argument about not being physically able to hold the breath does not seem trustworthy (I understand it is made in answer to question whether one could hold their breath to extend their time of useful consciousness; for which the argument should have been no, you'd suffer barotrauma). $\endgroup$ – Jan Hudec Oct 16 '14 at 7:25
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    $\begingroup$ @JanHudec Diving is rather different: lung over-expansion injuries occur when the diver runs out of air, holds his breath and ascends. In that situation - underwater with no air - your instinct is indeed to hold your breath and that's what the training you mentioned tries to overcome. Because the decompression occurs gradually as the diver ascends, not suddenly as in rapid aircraft decompression, it's easy to hold your breath until you reach a dangerous point; this is very different from the sudden shock of an aircraft decompression. And indeed the context for the quote is extending TUC. $\endgroup$ – Pondlife Oct 16 '14 at 12:32

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