Date: 201904
Local time of day: 1801-2400
Location: ZZZZ.ARTCC, FO
Flight conditions: VMC
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZZ
ATC / advisory: Center ZZZZ
Aircraft component: Engine
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Situational Awareness
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; Flight Crew Inflight Shutdown; Flight Crew Returned To Departure Airport
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: In cruise at FL290 approaching ZZZZ1; the First Officer and I noticed the left engine oil quantity at 1 quart and the left engine oil pressure slowly dropping; while the right engine remained stable. We called dispatch immediately and had a phone patch to [Maintenance Control] to discuss the issue. The oil pressure continued to drop during our roughly 3 minute discussion. Based on our current position; we all agreed the safest and most prudent course of action was to divert back to ZZZZ. The First Officer immediately called for the 2 Relief Officers; who were currently on break; to return to the cockpit. Everyone was briefed on the situation; as we had already turned back to ZZZZ. We informed the Purser of the issue and asked they begin picking up all trays and secure the cabin for landing in approximately 55 minutes. We also informed the passengers of our return to ZZZZ because of the situation. As we continued toward ZZZZ; the oil pressure continued to drop. We then [advised ATC] with ZZZZ1 ATC as it was becoming apparent we would eventually be shutting down the left engine; wanting priority handling to ZZZZ. We also began dumping fuel; which took 31 minutes to complete; to get us below an overweight landing situation. When the right engine pressure dropped to 14; we elected to disarm the left auto throttle and bring it to idle. We descended to FL240. Within 3 minutes of descending; the oil pressure was reading 9; the oil quantity was 0; [using] the ECL [Electronic Checklist] [for] the Engine Shutdown Checklist. We shut the left engine down as per the checklist. The Purser was notified of the current situation (TEST) and prepared the cabin as necessary. We asked ZZZZ Center to coordinate fire trucks at the airport for our return. We briefed an ILS to [Runway] 16R single engine auto land approach. We landed in ZZZZ without incident; taxied to a hardstand gate and deplaned passengers to buses. The ZZZZ Aviation Authority came on board the aircraft; asked us to write an incident report and took photos of our licenses and medicals before releasing us to leave the aircraft. I spoke directly with the [Maintenance Control] and Dispatch just prior to ZZZZ authorities boarding the aircraft; recapping the entire incident. [We] debriefed with our local mechanics of the engine issue and parameters we encountered prior to shutting down the left engine before leaving the aircraft and returning to the hotel. The incident began 53 minutes into the flight. We were back in ZZZZ in less than 1 hour after the incident began.


Second narrative: Preflight; taxi; and take-off accomplished uneventfully. Relief Officers released to rest areas.  Approx. 45 mins later; flying crew requested relief crews to return to cockpit due to system malfunction. Left engine oil quantity had reduced to 0 quarts and oil pressure was slowly decreasing below 29psi. Continued to decrease at a rate of approx. 1 psi per minute. Decision was made to return to ZZZZ1.  Engine shutdown accomplished in accordance with FM and single engine approach and landing planned. [Advised ATC] in accordance with [Company] FOM with ZZZZ Control. Hand-off to ZZZZ1 ATC uneventful. Several questions answered to appraise ATC of situation; and what our intentions were. Company was notified; and pertinent coordination accomplished.  Checklists were accomplished in accordance with 777 FM and [Company] FOM.  Flight attendants were brought up to speed with the situation as quickly as possible as the situation developed.  Numerous PA announcements were accomplished in order to keep passengers informed and to relieve any unnecessary anxiety. Company sent several requests for information and suggestions late in the situation. Caused minor distraction; and crew determined that communication could wait until safely on the ground.  Captain continued to function as Flying Pilot where she uneventfully executed auto land on Runway 16R at ZZZZ1. We taxied clear of runway and proceeded to hard stand where we shut down the aircraft and accomplished terminations checklists. Uneventful. Coordination accomplished to transport. Passengers to terminal building. Uneventful. Captain did a great job of handling the situation and fully utilizing as many resources as possible.  Delegated duties and kept everyone engaged. Good job. ZZZZ1 ATC /FAA requested statements and were given by pilots.  Upon external inspection of left engine; it appeared that a piece of material; maybe heat shielding was lodged in very aft exhaust hole on left engine.


Synopsis: B777 flight crew observed low oil quantity and shutdown engine and returned to departure airport.