B747-400
Maintenance Powerplant; Maintenance Airframe
Communication Breakdown; Situational Awareness; Training / Qualification; Confusion
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Chart Or Publication; Procedure; Manuals; Human Factors
I was asked to reverse the securing of oxygen bottles on a B747-400 aircraft per Maintenance Manual (M/M) [Servicing Chapter] 12-00-98. The item was on Page 207; Item (5). The sidewall where the O2 oxygen bottles are located was taken down and left open. I preceded to open and safety the six bottles. The Aircraft Maintenance Manual (AMM) does not mention whether the O2 bottles are for crew or passenger. I opened and safetied six passenger O2 bottles. Later; when the flight crew requested crew O2 service due to pressure of 1190 PSI; crew oxygen bottle was found to be closed and not safetied. I did not see an open panel with crew O2 bottles; they were not mentioned in the AMM; and [I] did not perform any maintenance on them. The crew oxygen was then serviced to full.
During maintenance on a B747-400 aircraft a Mechanic was directed to safety wire oxygen bottle manual shut-off valves in the 'Open' position. Mechanic was later informed the flight crew oxygen bottle was found in the 'Closed' position.