Date: 201706
Local time of day: 0001-0600
Location: ZZZZ.Airport, FO
Flight conditions: IMC
Weather elements / visibility: Thunderstorm
Light: Night
Aircraft: B747-800 Advanced
Operator: Air Carrier
Operating under: Part 121
Mission: Cargo / Freight / Delivery
Flight phase: Cruise
Reporter organization: Air Carrier
Reporter function: Captain; Check Pilot
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Second reporter function: First Officer
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: Upon reaching our destination airspace at approximately XA:35; ATC asked us to hold 70 miles from ZZZ VOR due to large thunderstorms over the airport. Several other aircraft destined for [the] airport were also holding. ATC made it clear that no aircraft were being permitted to make an approach to the airport and would not provide any EFC times. After entering holding; I calculated a 'bingo fuel' (minimum fuel at which I would no longer tolerate holding and would proceed to our designated alternate) of 20.5 metric tons. This 'bingo fuel' was the sum of 13.3 tons of fuel to fly 1 hour and five minutes to [our alternate] and additional 7.2 tons of fuel in reserve. This would allow us to fly to the alternate; make an approach; go missed approach--returning to the radar pattern--then fly one more instrument approach and safely land. As time passed while we held as directed; other aircraft expressed their concern to ATC regarding their limited fuel quantity. A couple of other aircraft began to divert to their designated alternates. At approximately XA:45; I called approach two or three times to tell them we would have to divert to our alternate soon due to the lack of fuel onboard. The controller did not answer any of my calls. In my opinion; the controller had become overwhelmed with the number of aircraft requesting to divert to their alternates. At XA:48 with 21.8 tons of fuel and with no indication that the weather would clear over the airport in a timely manner; I asked approach control to give us vectors to our alternate. Even after asking three or four times; the controller did not acknowledge any of my requests. At approximately XA:50; I elected to proceed to the alternate. Even after the ATC controller did not reply to my calls. Shortly after stating 'fuel emergency' several times; I transmitted that we were leaving holding and proceeding to [alternate] airport by way of ZZZZZ fix at our present flight level. Even then; the ATC controller did not respond. At this point; we looked up other frequencies and attempted to contact air traffic control for assistance. At approximately XA:57; we received a voice request over guard frequency (121.5) asking us to return to our previous controllers frequency. We did so and the controller asked if we would like a higher altitude to proceed to our alternate. I requested FL320 and we were given FL300. It seemed to me as if it was now a different controller on duty; as the voice was not the same as the original controller.At approximately XB:13; the controller told us that airport was now open and accepting approaches and was asking if we wanted to return to land. I replied that this would be acceptable; providing we would not be holding prior to landing. With 16.7 tons of fuel remaining; we decided it would be safe to return to [original destination].Although approach gave us extended vectors north of the airport; our approach and landing was uneventful. We landed with approximately 12.1 tons of fuel as opposed to our planned landing fuel of 21.9 tons; a difference of 9.8 tons. Our total flight time was 5 hours 52 minutes; as opposed to the scheduled flight time of 4 hours 51 minutes; making our flight time an additional one hour and one minute more than scheduled.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B747-800 flight crew reported being issued a hold without EFC time due to weather.