Date: 201309
Local time of day: 1201-1800
Location: ZZZZ.Airport, FO
Flight conditions: IMC
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
ATC / advisory: Tower ZZZZ
Aircraft component: Powerplant Fuel System
Reporter organization: Air Carrier
Reporter function: First Officer; Relief Pilot; Pilot Not Flying
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: After engine start and initial power increase for taxi we got an engine fuel filter EICAS message. We returned to the blocks for local Maintenance to repair the problem. They estimated a one hour repair. The repair required opening the aft cowl of the left engine. It appeared that the lower aft latch was not released; so when the cowl was attempted to be opened the assembly jammed. It took over an hour for the mechanics to get the bound release to unlatch before repair could be initiated. Once access was obtained; they replaced the fuel filter and bypass sensor. Overall the repair took more than two hours to accomplish.  A flight crew engine run was accomplished at idle power. No problems were noted.The next flight segment had no maintenance malfunctions during ground operations. During flight; however; the same EICAS message reappeared shortly after takeoff. The message seemed to be intermittent; but being more prevalent at higher power settings. We entered holding to assess the issue and coordinate with Dispatch and Maintenance Control. It was determined that the safest course of action would be to return. An overweight landing was accomplished with the concurrence of Dispatch and Maintenance. The touchdown was normal. After that return to the gate; the local mechanics wanted to release the aircraft with a diagnosis of a wiring issue causing the fuel filter message. As this was an ETOPS flight over the Pacific Ocean we wanted more assurance that the message was indeed a false indication and not a true predictor of a fuel related engine failure. Due to an airport curfew there was not sufficient time to further troubleshoot the problem.


Second narrative: On initial taxi out having both engines running; we received both an EICAS Status message - Engine Fuel Filter Left. We returned to the blocks where Maintenance replaced both the filter and the differential pressure switch. Per SOP and with written authorization from Maintenance Control; pilots performed an idle engine run at the gate with no further EICAS or Status messages displayed. On second taxiout; all indications were normal. Takeoff was normal. At approximately 2;000 FT AGL in the climb; we again received both an EICAS and Status message - Engine Fuel Filter Left. We ran the checklist as we climbed to FL150 to hold at the VOR. All flight crew agreed that we needed return as this was an ETOPS flight. Both Dispatch and Maintenance Control were notified. Crew elected to do an overweight landing versus dumping fuel. The overweight landing checklist was accomplished in holding pattern as well as the diversion guide QRH. The approach was normal. Our landing weight was 571.5 with a target approach speed of 159 KTS. The touchdown/landing was soft and uneventful.


Synopsis: B777 flight crew describes the steps taken to correct a fuel filter EICAS message that returns after takeoff and results in a return to field for an overweight landing.