B747-400
Maintenance Airframe; Maintenance Powerplant
Maintenance Technician 30
Distraction; Situational Awareness; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors; Incorrect / Not Installed / Unavailable Part
During the walk around inspection of a routine line maintenance turnaround; a fuel leak was observed at the Number-3 Engine pylon. After trouble shooting & investigation it was determined that a replacement fuel line was required & the flight was cancelled. The unserviceable fuel line was removed by the afternoon shift who wrote a comprehensive turnover. The new line was ordered from the manufacturer with all supporting hardware & arrived the next day. During the installation of the new fuel line; the aircraft was moved from the remote stand to the departure gate & Maintenance was informed that the scheduled departure time had been moved up by [two hours]. The interruption & time pressure resulted in distractions; although the new fuel line was fully installed with it's couplings tightened & leak tested as per Aircraft Maintenance Manual (AMM) procedures; I failed to install the safety wire lock on the fuel line coupling. After the flight departed I was reviewing the AMM procedures & discovered that the fuel line required a safety wire lock. I immediately informed the downline station where the aircraft was stopped & the safety wire lock was installed. I have no excuses for not completing the safety wire task but feel the distraction of moving the aircraft; the rescheduling of the ready time & not being involved with the removal of the unserviceable line the day before; all contributed to my mistake. After the aircraft was moved I should have reviewed the AMM tasks from the beginning & should not have been distracted by external factors.
A Line Aircraft Maintenance Technician (AMT) realizes he had not installed a required safety wire lock on a fuel line coupling that was replaced in a Number-3 Engine pylon prior to departure of a B747-400 aircraft. Technician noted how distraction of moving the aircraft; rescheduling departure two hours sooner and not being involved with the removal of the unserviceable line the day before all contributed to his error.