MD-11
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
General None Reported / Taken
Human Factors; Procedure
First Officer got up to go to the restroom. I tried to don my oxygen mask; but when I tried to remove it the entire compartment that houses the mask came out in one piece; rendering the mask unusable because I could not remove it from the compartment. This occurred just prior to top of descent. Needless to say an event that would have required the use of oxygen would have been a problem. I would have had to use the mask in the observer seat behind me. Prior to departure a review of the maintenance history in the logbook showed that the Captain's oxygen compartment was replaced. My preflight inspection of the oxygen system does not include inspection of the compartment. Maintenance did not secure the compartment screws to insure the installation was complete. The compartment was placed in the slot but not screwed in. This can be prevented in the future by maintenance insuring that the compartment is properly secured. Next time I see a history of maintenance on my oxygen compartment I will check that it is screwed in completely.
MD11 Captain reports the entire oxygen compartment coming out of the side console when use is attempted in cruise. The retaining screws had not been installed after Maintenance had replaced the unit.