What happened
On 11 December 2008, at 22:53 UTC, a Finnish Commuter Airlines EMB-145LU (registration OH-EBE) was taxiing to its parking stand at Kemi-Tornio aerodrome following a flight from Helsinki. During the taxi, a fire broke out in the aircraft's auxiliary power unit (AP/U). The flames spread to the APU tailpipe and the APU compartment.
Following the landing, the crew attempted to start the APU, but the start failed. Simultaneously, the aircraft experienced a major electrical disturbance. The pilots were preoccupied with managing the APU generator's failure to couple and the unexpected activation of the electrical system's overcurrent protection feature. Because the aircraft's fire detection system failed to provide an alert, the crew was unaware of the fire until a ground crew loadmaster noticed the flames and alerted the cockpit via hand signals and by entering the aircraft.
During the incident, the electrical failure caused the cabin lighting to fail, which hindered the flight attendant's ability to manage the cabin and slowed the evacuation of passengers. The passengers deplaned while the fire was still active. The fire was eventually extinguished using the aircraft's onboard fire suppression system.
The investigation
The investigation established that the fire originated in the APU, which was noted to be in poor condition and partially damaged prior to the event. The investigation examined the failure of the APU fire detection system, the simultaneous electrical malfunctions, and the crew's response. It was also noted that air traffic control was neither aware of the fire nor informed of the incident, and the local emergency services did not react during the fire itself.
Findings
- The primary cause of the fire was a fire breaking out in the APU during taxiing.
- The aircraft's fire detection system failed to alert the crew because the fire detection element was likely not sufficiently exposed to the flames.
- The severity of the incident was exacerbated by the simultaneous occurrence of multiple system failures, including the APU generator coupling failure and the unexpected activation of electrical overcurrent protection.
- There were deficiencies in crew resource management, specifically regarding cockpit cooperation and adherence to standard operating procedures.
- The airline had not updated its operations manual (OM-B) to reflect recent manufacturer revisions (AOM) regarding electrical overcurrent protection.
- The crew failed to make all necessary entries in the technical logbook regarding the observed faults and incidents.
- There were no 0 fatalities or injuries, though the aircraft sustained minor damage.