Date: 201506
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Aircraft component: Main Gear Door
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Situational Awareness; Workload; Distraction; Communication Breakdown
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR; Ground Event / Encounter FOD
Detector: Person Air Traffic Control
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Equipment / Tooling; Human Factors; Staffing
Primary problem: Human Factors

Narrative: I was assigned to work the Center Axle Inspection on a B777. I used a long wooden 2'x4' as a tool to align the truck with the inner cylinder on the LH Main Landing Gear (MLG). When we achieved alignment; at approximately late morning; I placed the tool on the outer lip of the main landing gear wheel well door. We then proceeded to reassemble the LH main landing gear center axle. Later that evening I was performing Brake Operational checks in the cockpit with the Inspector. When the checks were complete; the mechanic on the ground began to service the Center system hydraulic fluid. I was observing the quantity in the cockpit and asked the mechanic on the ground to close the landing gear doors so we would have an accurate quantity reading. When we finished the fluid service; I went to the ground; completed the Job Card and began to clear away the remaining tooling and equipment so the aircraft could be taken out of the hangar. Apparently; the tool was still on the door when the door was closed and fell out of the wheel well when the aircraft went on a flight the next day. Aircraft/Cabin potential damage caused By FOD. [Recommendations]: 1) The tool should not have been placed on the door.2) The door should have been cleared better before it was closed.3) The tool was an old; dirty 2x4; brown and black in color. A brightly painted board would be easier to see.4) Only two mechanics were assigned to finish this job which included down jacking the aircraft; removing the jacks; servicing the landing gear struts and transitioning the aircraft from Air Mode to Ground Mode.


Second narrative: Just after takeoff Tower said another aircraft reported that something fell from our aircraft. We asked them to let us know what they found. No negative indications from aircraft instrumentation. No negative flight control effects. We asked Flight attendants if they noticed abnormal noise or sights - nothing. It was reported that airport ops found a 2x4 on the runway. We consulted Maintenance; determined nothing amiss and continued to destination.


Synopsis: An Aircraft Maintenance Technician (AMT) reports placing a 2' x 4' board against the outer lip of the Left Main Landing Gear (MLG) door after completing a Center Axle alignment on a B777 aircraft. MLG door was closed later; but the 2X4 fell out of the wheel well after takeoff also told from the perspective of the Captain of the flight. Distractions; workload and limited staffing were contributors.