A320
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 187
Situational Awareness; Time Pressure
Aircraft Equipment Problem Critical
General None Reported / Taken
Aircraft
After quick donning the Captain's O2 (Oxygen) mask a malfunction occurred whereby the hose that is attached to the bib/nipple on the mask portion became detached. O2 escaped uncontained for approximately 15 sec. The crew O2 system lost 250 psi. I stopped the runaway O2 by using the 'reset' switches inside the O2 mask compartment. This could have been a more serious event if this mask failed during a Rapid Descent.
Flight Crew experienced failure of the Captain's Emergency Oxygen Mask during cruise.