Commercial Fixed Wing
Time Pressure; Confusion; Communication Breakdown; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Ground Event / Encounter Fuel Issue
Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed
Human Factors; Company Policy; Procedure
We began our duty day at XA30 Z on date in ZZZZ; for a flight to ZZZZ1; continuing to ZZZ.  Upon arriving in ZZZZ1 the ground handlers removed existing pallets and started loading the outbound cargo; before fueling started. Approximately 30 - 45 minutes later we had about a 16 ton imbalance with all of the fuel in the left wing tanks and center tank; and fuel was venting overboard; after the fuel spill clean up the fueling process resumed and again stopped due to the mechanic onboard the flight was not experienced on the aircraft type; and could not figure out how to operate the valves and transfer fuel to the right wing tanks. With us as the flight crew not allowed to exit the aircraft in foreign country; had no other option but calling [company]; and keep them in the loop. At this time we are approaching our duty limit for the day in order to reach ZZZ; and we all agree to extend our day by X hours to get the job done; as described in the FARs. Numerous calls are being made to Dispatch; Maintenance Control in order to find help for the Mechanic who is outside supervising the fueling. Again we are approaching our duty limit; and calls are being made to Director of Operations Control; who hung up the phone on the Captain and to the Duty Officer who hung up the phone twice. What we were trying to accomplish was if the company had a contingency plan; or a plan B for us. As we had discussed this earlier; and rather sleeping on the aircraft; we were thinking more like proceeding to either ZZZZ2 or fly back to ZZZZ to rest; which was denied by the Duty Officer. We ended up spending the night on the aircraft; and after the curfew was lifted in ZZZZ1 we were able to get the required paperwork and fuel for departure. Finally arrived in ZZZ with no issues almost XX hours after the duty day had originally started. Would like to add that ALL phone conversations to operations control; maintenance control; Director of operations control and Duty Officer were made using speaker phone and was heard by the entire crew on the aircraft.[Caused by] inexperienced Mechanic operating and supervising the fueling process. The company needs to have a contingency plan; and plan B.By changing the scheduling procedures; have a dedicated crew fly between ZZZZ - ZZZZ; and use heavy crews for the rest; and provide better training for maintenance personnel in order to understand the aircraft type refueling process.
Air carrier First Officer reported that a ground delay caused by fueling imbalance resulted in the crew approaching duty time limits. Due to the foreign country's COVID-19 restrictions and company procedures; the crew had to remain on the aircraft for required rest.