Date: 201912
Flight conditions: VMC
Light: Night
Aircraft: B767 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Aircraft component: Fuel
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew; Person Passenger
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; Flight Crew Diverted
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During my rest break; I was notified that a passenger had noticed a fluid leak coming from the top of the left wing. The Captain had requested I investigate. I inspected the wing and immediately noticed a stream of fluid emanating from the top of the left wing from the fuel cap. I returned to the flight deck. I'd already briefed the crew on this same situation having experienced it the month before on the same aircraft. We read through the QRH procedure but agreed it would not be prudent to shut down an engine and that it would make the situation worse. We reviewed the FOM diversion guide. We agreed it was prudent to divert as we had no way of knowing how severe the leak was and we certainly didn't want to be over an ocean with fuel leaking. We would be landing overweight (even after dumping fuel); and began looking for airports with longer; dry runways. We felt ZZZZ was our best option and advised ATC. After some time; ATC advised us that ZZZZ would not take us for a fuel leak despite our [priority] status and they felt it was unusual for us to be passing other airports. We explained that we had assessed those airports and that there was either insufficient runway lengths or wet runways and that we were overweight. We landed in ZZZZ1 safely (originally we elected not to go there because of the wet runway but then dispatch indicated it was dry). Passengers seemed to be in good spirits until we got to baggage claim and then they were irritated by the slowness of getting their luggage. There was also some difficulty (because of staffing limitations); getting passengers to the busses despite there being numerous announcements over the airport PA system.


Second narrative: At about XA00Z during cruise; one of the flight attendants told us that a passenger was seeing fluid coming off the left wing. The flight attendant could also see the fluid from the left wing; with none coming from the right wing. We asked that the Relief Pilot also check. He too reported fluid coming from the area of the fuel cap; and coming off the left wing (a photo and video of this were later sent to Maintenance). The Relief Pilot rejoined us in the cockpit; and we briefly discussed that the same aircraft had the exact same type of fluid flow off the left wing from the exact same area about a month earlier - coincidentally; the Relief Pilot had been on that flight; too.The fuel leak non-normal checklist (QRH 120.6) describes a visual sighting of fuel coming from the engine strut or engine; which was not what we had. Nonetheless; as we believed that the fluid coming off the wing indicated a minor fuel leak; we consulted the checklist to see whether 1) There was any information which we might find useful; and 2) To be prepared in case the leak worsened into something described in the checklist.From the time we were informed about the fluid on the wing until well into descent to our diversion airport; we watched for indications of possible fuel leak in the fuel leak checklist (QRH 120.6); as well as comparing fuel onboard to both the flight plan and ACARS. At no time did we see anything from any source which indicated a fuel leak other than the visual sighting on the wing.We consulted with Dispatch and Maintenance via SATCOM; and everyone agreed that it was likely a fuel leak; and that diversion was the prudent course of action. This decision was made around XA30Z.We knew that we would be landing overweight even after dumping all remaining fuel from the center tanks; and we all agreed that an airport which had both long and dry runways would be best.Given that we knew we would be diverting; dumping fuel; and landing overweight; as per our training we requested priority hanlding with ATC.The items in the Diversion Planning Guide were covered partly during our call with Dispatch and Maintenance Control; and partly on our own afterwards. Rough performance calculations indicated we would need nearly 7;000 feet of runway at our estimated 345;000 lb. landing weight with wet conditions as per flight manual; which seemed to be the case in the closer airports. If we used the brakes hard to stop shorter; we thought we might melt the fuse plugs before we could get to a gate as per flight manual. ZZZZ was the best fit of dry and long runways. We therefore told ATC that we would divert to ZZZZ; and requested clearance to dump fuel. We received initial vectors towards ZZZZ; and were told to wait to begin our fuel dump.While waiting to begin the fuel dump; I spoke with the Purser and gave her the procedural information. I then told the passengers the nature of our problem; and that we were diverting to ZZZZ.Clearance to dump fuel came perhaps 5-10 minutes later. Before we began; the Relief Pilot made an announcement to the passengers that we would be dumping fuel so they would not be startled to see more fluid coming from the wings. We dumped all fuel remaining in the center tanks as per the fuel jettison checklist. This totaled about 14;500 lbs dumped at cruise altitude over the sea.After some time and perhaps a frequency change; ATC told us ZZZZ would not accept us. ATC's verbiage was something like 'ZZZZ won't accept a fuel leak diversion aircraft' or 'ZZZZ won't accept you as a diversion aircraft with a fuel leak.' Aware of the note on the ZZZZ 10-XX page about use of ZZZZ for emergencies and that there were other adequate airports to use; we didn't contest this. ZZZZ was the best choice; but not the only choice for a safe outcome.While considering our next best option with Dispatch; numerous other airports were discussed with consideration for our overweight condition as per FOM. This was complicated by a temporary paper jam in the ACARS printer; and intermittent WiFi reception in the cockpit; both of which slowed the gathering of information necessary for us to make a good decision.At some point in this stage; ATC asked us about our priority status; saying that usually in their experience priority aircraft have to land ASAP. Realizing the error in the prior priority declaration; we made the decision to downgrade our status.We made the decision to land at ZZZZ1 due to the length of the runway; coupled with a new report calling the surface Dry (upon arrival; we found the surface to be wet; though with no standing water. Braking was good). Passengers were briefed about the change in diversion airport during the descent phase. We landed on Runway XXL at 340;000 lbs; and after arrival at the hard stand area; made appropriate logbook entries for maintenance in re the overweight landing and speed when brakes were applied. The entire crew stayed with the passengers until they were all off the aircraft and into the terminal area with appropriate assistance.


Synopsis: B767 flight crew reported a fuel leak that resulted in a diversion.