B777-200
Maintenance Powerplant; Maintenance Airframe
Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors; Chart Or Publication; Incorrect / Not Installed / Unavailable Part
I was assigned to work an Engineering Order on a B777-200 aircraft. The Job Card was mostly completed when I was asked to pick up on the work turnover that was already in progress. I started at Step 10; A;(7). When I arrived at the aircraft; the [flight crew] Oxygen (O2) stowage box was already installed with a completed Leak Check. The stowage boxes were already installed but not signed for; so I checked to make sure that all the fasteners were tight. From what I have been told all four O2 Mask microphones were not connected to the back side of the stowage box. There were several people that had been working on this Job Card over several shifts and I was tasked to complete an already started job. Turnovers from [Maintenance] crew to [Maintenance] crew need great improvement and the Avionic's Department needs more Operational Checks prior to release of the aircraft. Airworthiness Directive.
An Aircraft Maintenance Technician (AMT) was informed that all four flight crew Oxygen (O2) mask microphones on a B777-200 aircraft were found not connected to the back side of their stowage boxes. Lack of adequate Maintenance turnover communications between shifts and the need for more Avionics's Operational Checks prior to aircraft release were noted.