What happened
On a scheduled flight from Vancouver International Airport to Calgary, an Air Canada Airbus A3/300-300, registration C-GHKX, experienced a substantial fuel leak shortly after departure. While the flight crew received no cockpit warnings or abnormal engine indications, air traffic control notified the pilots that a large amount of smoke or vapor was emanating from the number 2 engine. The crew declared an emergency and promptly returned to Vancouver.
Upon landing, the pilots shut down the affected engine. While aircraft rescue and firefighting personnel noted fuel leaking from the engine, no fire was present. The aircraft was eventually towed to the terminal, and all 92 passengers and 6 crew members deplaned without 0 injuries or damage to the airframe.
The investigation
The investigation focused on maintenance performed the previous day. During a routine service check, technicians had identified a leak from the air/oil heat exchanger. However, a clerical error on the maintenance office duty board incorrectly indicated that a fuel/oil heat exchanger required replacement instead of the air/oil heat exchanger.
Because the technicians did not consult the Troubleshooting Manual (TSM) to resolve the discrepancy, they unnecessarily disconnected the low-pressure (LP) fuel line. During the repair, a retainer slid down the fuel line and became hidden from view. The technicians then reassembled the LP fuel line coupling without this retainer in place.
Following the work, an engine run-up was performed at idle power. Because the engine vibration and fuel flow at idle were insufficient to stress the connection, the line remained attached. A subsequent ground inspection was also inadequate, as it was conducted from the ground rather than an elevated position, and did not utilize a developer to assist in leak detection.
Findings
- A maintenance office error led to the unnecessary disconnection of the LP fuel line.
- The technicians failed to follow the Aircraft Maintenance Manual (AMM) and did not use the TSM to clarify the task.
- The LP fuel line detached from the heat exchanger during takeoff due to the missing retainer and the increased fuel pressure and vibration associated with takeoff power.
- The lack of a high-power engine run-up meant the faulty installation was not detected before flight.
- The airline had not yet implemented Airbus Service Bulletin A330-28-3080, which provides an alert for significant fuel loss.