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

Please include links to statistics.

  • 4
    $\begingroup$ So infrequently that any statistics, if they exist, will be meaningless. $\endgroup$
    – Simon
    Mar 19, 2017 at 15:58
  • 2
    $\begingroup$ Not statistically significant, almost no matter how you slice it. Flying Hours/Deployments, Flights/Deployments, Aircraft/Deployments... $\endgroup$
    – Ron Beyer
    Mar 19, 2017 at 16:14
  • 1
    $\begingroup$ @RalphJ: Opinion, because, in my opinion, there is no mandatory notification for such event. $\endgroup$
    – mins
    Mar 19, 2017 at 19:30
  • 1
    $\begingroup$ @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. $\endgroup$
    – Simon
    Mar 19, 2017 at 20:01
  • 3
    $\begingroup$ 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. $\endgroup$
    – Terry
    Mar 19, 2017 at 21:37

1 Answer 1


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!


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