B737-800
Maintenance Airframe; Maintenance Powerplant
Workload; Troubleshooting; Situational Awareness; Distraction; Communication Breakdown; Time Pressure
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Company Policy; Aircraft; Human Factors; Procedure
Upon departure the flight crew had #1 Engine Generator [IDG] fall 'off-line' and had moderate vibration through the B737-800 aircraft; causing an air interruption. Upon landing and going into reverse thrust; the outboard fan cowl was blown off.Heavy workload; worked three overnight aircraft. Aircraft X had two grounding items. Number one engine outboard fan cowl was opened to troubleshoot one grounding item. Gave information to Lead Mechanic to relay information to Technical [Support] for disposition. Shifted focus to third Overnight Check that just arrived on the gate. Grounding item on the aircraft was subsequently deferred and no further action was required. Suspect fan cowl was not properly secured.
Reporter stated that prior to the air turnback incident; the # 1 Engine Fan Cowl was opened to troubleshoot a Tach Generator write-up involving the Power Management Control (PMC) on the CFM-56 engine. He suspects that when he gave the Lead Mechanic their trouble shooting turnover and information about the fan cowl still being opened; that info was not clearly passed on to Technical Support who eventually deferred the write-up prior to departure.Reporter stated the # 1 Engine Generator actually went 'Off-Line' when the generator was damaged by the fan cowl as the cowl departed the engine during reverse thrust.
Aircraft experienced a Generator message and buffeting after takeoff. Aircraft air interrupted and returned. Upon touchdown and thrust reverser deployment; left engine outboard fan cowl blew off. Suspect left engine fan cowl not completely secured due to large workload; distraction and mis-communication.
Two Line Mechanics report that a B737-800 aircraft experienced moderate buffeting through the aircraft after departure; requiring an air turn-back. On landing; while going into reverse thrust; the #1 Engine Generator had fallen 'Off-Line' as the Outboard (O/B) fan cowl was blown off the same engine.