Maintenance Airframe; Maintenance Powerplant
Situational Awareness; Troubleshooting
Aircraft Equipment Problem Critical
General Maintenance Action
Aircraft; Procedure; Human Factors
I Removed and Replaced (R/R) the Fuel Flow Transmitter on the Left-Hand Engine (# 1 Engine). This was due to an Engineering request that it be replaced since there was a history of high fuel consumption. When the Task was completed; I performed an Engine Run to [do] Operational/Leak Check of the engine. No faults were noted. The aircraft flew ZZZ to ZZZ1 with no faults. Upon landing on the return ZZZ1-ZZZ trip; when the Thrust Reversers were deployed; the Left-Hand Engine shut down. When the aircraft was inspected; it was discovered the gasket for the [Fuel] 'In' tube at the Fuel/Oil Cooler had failed. I had replaced the same gasket the night before as part of the Fuel Flow (F/F) Transmitter replacement. At this time I am not aware if this is the result of a gasket failure or procedural error on my part.
Reporter stated the Fuel/Oil Cooler is mounted on the right side of the combustion case on GE CF6-8 engines. He had to remove a fuel line (tube) that ran from the Fuel Flow (F/F) Transmitter to the Fuel/Oil Cooler in order to replace the F/F Transmitter. The metal gasket he installed between the 'In' tube coupling flange on the fuel line and the Fuel/Oil Cooler housing flange has an 'O-Ring' type seal on both sides of the gasket. When Maintenance opened-up the CF6 Engine cowling after the engine had shutdown on landing; a small amount of fuel was noticed on the engine. But; when the Engine Leak Check Run was performed; fuel was spraying everywhere.Reporter stated a piece of the 'O-Ring' seal was missing from the metal gasket; but he doesn't know if one; or both seals were cut; or missing a seal section when he installed the metal gasket. The B767-300 did fly two legs without any known problems prior to the shut down. He noted that having the engine shut down on landing was a better situation than having the seal fail on Takeoff with a potential engine fire. A new gasket was installed; Engine Run accomplished; no further leaks.
A Line Mechanic reports the left engine on a company B767-300 aircraft had shutdown on landing when the thrust reversers were deployed. A metal gasket he had installed between the fuel/oil cooler housing and the fuel 'In' tube connection to the fuel/oil cooler had failed.