B767-300 and 300 ER
Maintenance Airframe; Maintenance Powerplant
Time Pressure; Communication Breakdown; Troubleshooting; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Inflight Shutdown; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft; Procedure
During a maintenance evaluation test flight; the right engine had an un-commanded shut down and could not be restarted. It was found the fuel outlet tube coming from the MEC [Main Engine Control] going to the fuel flow transmitter had come loose and was leaking from the MEC  side. The last documented time this hose was disturbed was during the right engine MEC replacement. When the tube was installed a new gasket was used and noticed no other defects with the installation of the tube. The bolts attaching the end were not drilled for safety wire but no defects with the run on torque were noticed. The aircraft had been run multiple times for high power runs and idle runs for troubleshooting and no leaks had shown up in the few days the aircraft was out of service. The tube may have disturbed during the fuel pump replacement for access to the oil scavenge tubes but it is not a part of the task.
B767 Technician reported discovering fuel lines on engine were loose and caused an inflight shutdown and return to departure airport.