Maintenance Airframe; Maintenance Powerplant
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors
I was doing the A CHECK but I did not notice that the oxygen mask was disconnected. I was at the terminal working the night shift and nobody else was involved. The FAA Inspector made his inspection and noticed this issue. I reconnected the oxygen mask to the bottle and made an entry in to the log book. I made the inspection and saw the bottle with oxygen mask in the top and it appeared to be connected.
A Maintenance Technician did not recognize that an oxygen mask was not connected to the bottle until it was pointed out by an FAA Inspector.