What happened
On June 9, 2007, an Air Finland flight, operating as KKK7214, arrived at Antalya, Turkey, from Alesund, Norway, with 165 passengers and 8 crew members. During the descent, the flight crew noticed a slight imbalance between the fuel levels in the left and right main tanks. Believing the discrepancy to be within normal error margins, the pilots utilized cross-feed to equalize the tanks and did not initiate Quick Reference Handbook (QRH) procedures for a fuel leak.
Upon arrival and during taxiing, a "FUEL CONFIG" message appeared on the Engine Indicating and Crew Alerting System (EICAS) and the fuel configuration light illuminated. The crew confirmed a significant imbalance, with 1800 kg of fuel in the left tank and only 1000 kg in the right. Following the shutdown of the right engine, substantial amounts of fuel were observed leaking onto the ground near the engine. The aircraft's arrival prompted an immediate response from the airport fire service, which used water to wash away the spilled fuel to mitigate fire risks.
The investigation
The investigation focused on the mechanical failure of the right engine's high-pressure (HP) fuel pump and the crew's response to the fuel imbalance. Investigators examined the maintenance history of the pump and the operational decisions made by the flight crew during the approach and taxi phases. The investigation also looked into the handling of the faulty component after its removal.
Findings
- The primary cause of the incident was the mechanical failure of the high-pressure fuel pump on the right engine. A threaded plug inside the pump's drive shaft loosened, causing the seal surfaces to separate and allowing fuel to escape.
- The flight crew did not utilize the QRH checklists during the flight because they did not initially recognize the imbalance as a confirmed leak.
- The use of idle reverse thrust during landing likely dispersed the leaking fuel around the engine, increasing the risk of ignition from hot exhaust gases.
- The crew failed to shut down the right engine immediately once the fuel leak was confirmed on the ground.
- A ground mechanic attempted to alert the pilots to the leak using hand signals, but the signals were unclear and not understood by the crew.
- There was a significant risk of fire from both the engine exhaust and the heat from the brakes contacting the spilled fuel.
- The faulty fuel pump was lost in a service provider's warehouse for several months, only being located in March 2008.
Safety action
Following the incident, Air Finland incorporated fuel leak scenarios into its simulator training and updated its Operations Manual Part A. The airline also reviewed the event during its Flight Safety and Quality Committee meeting. The investigator recommended that the airline enhance its oversight of the service providers responsible for component maintenance and tracking.