Accident Overview
On August 20, 2007, at approximately 10:33 JST, a China Airlines Boeing 737-800, registration B18616, was at Spot 41 at Naha Airport. The aircraft developed a fuel leak from the right wing, which ignited, causing a fire. An emergency evacuation was conducted. The Japan Transport Safety Board (JTSB) initiated an investigation.
Investigation Process
The JTSB investigation was conducted under Japanese law and ICAO Annex 13. Data sources included DFDR, QAR, CVR, ATC communications, and statements from flight crew, cabin crew, ground crew, and controllers. Video camera images were also analyzed. The Japan Aerospace Exploration Agency (JAXA) performed examinations as part of the fact-finding.
Fuel Leak and Fire
The investigation found that the fuel leakage originated from a puncture hole in the right wing. The downstop assembly of the slat mechanism was detached, and a missing washer was identified. The analysis examined the sequence leading to the fuel leak, the ignition of the leaked fuel, and the spread of the fire. The slat mechanism and its design were reviewed. Prior issues with the downstop assembly had been documented, and corrective actions had been taken through engineering orders.
Emergency Evacuation and Fire-Fighting
The emergency evacuation proceeded according to established procedures. Fire-fighting operations were carried out by the airport fire station. The report includes details on the mobilization of fire engines, travel time, and the fire-fighting system at Naha Airport. The timing of fire reports from the aircraft to the tower and from ground crew to the airport office was analyzed.
Other Findings
The investigation noted a difference in fuel quantity between the left and right wing tanks. The CVR operation was interrupted. The analysis also covered the track can damage and the time it occurred. Maintenance work on the downstop assembly and the quality control of the company were examined.