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In commercial passenger aviation, how frequent (or infrequent) is the case that oxygen masks deploy?

Please include links to statistics.

DeltaLima
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Sandro Carlos
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    So infrequently that any statistics, if they exist, will be meaningless. – Simon Mar 19 '17 at 15:58
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    Not statistically significant, almost no matter how you slice it. Flying Hours/Deployments, Flights/Deployments, Aircraft/Deployments... – Ron Beyer Mar 19 '17 at 16:14
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    @RalphJ: Opinion, because, in my opinion, there is no mandatory notification for such event. – mins Mar 19 '17 at 19:30
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    @RalphJ Are you expecting an answer which is not opinion based? Any answer, since there will be no meaningful measures, must be opinion based. I'll kick it off. In my opinion, once every 12.7 million person miles. – Simon Mar 19 '17 at 20:01
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    @mins Couldn't one work out an upper bound by looking at, e.g., cabin pressure loss? http://www.avherald.com/h?search_term=Cabin+pressure&opt=256&dosearch=1&search.x=-862&search.y=-106 – Řídící Mar 19 '17 at 20:02
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    @Keepthesemind: In that case it would be appropriate to change the question and ask directly for pressure loss events. It would be less ambiguous (e.g. the crew can deploy masks by accident by pressing a button in the flight deck, regardless of the pressure.) – mins Mar 19 '17 at 20:08
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    I'd be willing to bet serious money that there are far more deployments from hard landings and accidental deployments than from loss of pressurization. I'm embarrassed to admit it, but I made a hard landing in a 727 back in the 1980s that dropped a few masks in the back, and once while flying right-seat in a Citation, the left-seat guy accidentally deployed the masks. Neither I nor, to the best of my knowledge, any of my flying acquaintances ever experienced a loss of pressurization resulting in a deployment. – Terry Mar 19 '17 at 21:37
  • This is a good question. In my regular training I have to provide an answer to the underlying question (how frequent are aircraft depressurizations?) and in extensive research I have not been able to come up with a concrete answer, either current or historical. – J W Mar 20 '17 at 03:27
  • helpful post http://aviation.stackexchange.com/questions/34177/how-likely-could-there-be-a-loss-of-cabin-pressure – Prodnegel Mar 21 '17 at 16:57

1 Answers1

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Very, very rare, probably in the range of sinlge digits per 100,000 flights (for major first-world airlines, perhaps higher elsewhere).

I'll try to get you a more numeric answer tomorrow.

Posting an answer now so that I can edit it, evem if the question gets closed between now and then.

"Opinion based", horsefeathers!

Ralph J
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