Narrative:

I was flying an A321; relatively new. [During a] restroom break; I went to put the oxygen mask on; hose separated from mask; massive hissing and rapid oxygen pressure loss. Managed to stuff hose back into mask and stop leak. We considered diverting...but we had 1;600 psi left; so continued (sent heads up dispatch). Upon arrival; as soon as mechanic touched it; it fell apart; losing oxygen very rapidly until I assisted him in tying a knot in hose.very worrying implications: had I gone to use adjacent mask in decompression or smoke event; the number 1 mask would have fallen apart and first officer and captain would rapidly have run out of oxygen. Possible crew incapacitation and hull loss scenario here. The mask looked fine otherwise. I believe the outdated FAA regulation to don modern quick-donning masks is putting undetectable wear and tear on eros masks (no other country requires this anymore). Stuffing them back in the box repeatedly is not what they were designed for. In addition; many of the facemasks are getting scratched to the point that they would be difficult to see through in a real event. (In hindsight had I known the state of my [mask] in flight; I could have descended to 10;000 feet and diverted; and brought walk-around oxygen to the flight deck for smoke event possibility).undetected wear and tear on mask/hose connection is due to FAA regulation requiring quick-donning masks to be repeatedly deployed beyond their design specifications. Review of requirement to don mask when single-pilot when a modern quick-donning mask is installed. The eros-type masks were designed to negate this old requirement; and are not sturdy enough for repeated (1000's of times per year) extraction and re-stowing.

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Original NASA ASRS Text

Title: A321 flight crew reported an in-flight failure of the Captain's Oxygen mask.

Narrative: I was flying an A321; relatively new. [During a] restroom break; I went to put the oxygen mask on; hose separated from mask; massive hissing and rapid oxygen pressure loss. Managed to stuff hose back into mask and stop leak. We considered diverting...but we had 1;600 PSI left; so continued (sent heads up Dispatch). Upon arrival; as soon as Mechanic touched it; it fell apart; losing oxygen very rapidly until I assisted him in tying a knot in hose.Very worrying implications: Had I gone to use adjacent mask in decompression or smoke event; the number 1 mask would have fallen apart and First Officer and Captain would rapidly have run out of oxygen. Possible crew incapacitation and hull loss scenario here. The mask looked fine otherwise. I believe the outdated FAA regulation to don modern quick-donning masks is putting undetectable wear and tear on Eros masks (no other country requires this anymore). Stuffing them back in the box repeatedly is not what they were designed for. In addition; many of the facemasks are getting scratched to the point that they would be difficult to see through in a real event. (In hindsight had I known the state of my [mask] in flight; I could have descended to 10;000 feet and diverted; and brought walk-around oxygen to the flight deck for smoke event possibility).Undetected wear and tear on mask/hose connection is due to FAA regulation requiring quick-donning masks to be repeatedly deployed beyond their design specifications. Review of requirement to don mask when single-pilot when a modern quick-donning mask is installed. The Eros-type masks were designed to negate this old requirement; and are not sturdy enough for repeated (1000's of times per year) extraction and re-stowing.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.