What happened
On 12 June 2010, a Blue1 Airways AVRO 146-RJ85, registration OH-SAR, experienced a severe engine failure during its takeoff roll on runway 22R at Helsinki-Vantaa Airport. The pilots immediately aborted the takeoff at 03:47 UTC. The engine damage was significant enough that a substantial amount of engine components were left scattered across the runway surface.
Following the aborted takeoff, the aircraft vacated the runway. At the request of air traffic control, a maintenance worker performed a runway inspection. This initial inspection reported the runway to be clear of obstacles. Consequently, the air traffic controller cleared two subsequent transport aircraft for takeoff from the same runway. Shortly after these departures, the captain of OH-SAR contacted air traffic control via telephone to report the severe nature of the engine damage. This new information prompted a second, more intensive inspection involving two maintenance staff members and two vehicles. This second sweep successfully located the engine fragments, which were then cleared from the runway via sweeping.
The investigation
The investigation focused on why the engine failure occurred and why the initial runway inspection failed to detect the debris. Investigators determined that the engine damage was caused by a fatigue fracture at the root of a second-stage turbine rotor blade, likely resulting from excessive engine temperature. The investigation also examined the communication protocols between air traffic control and the airport maintenance unit during the inspection requests.
Findings
- The primary cause of the serious incident was that two aircraft were cleared for takeoff while engine debris remained on the runway, posing a significant risk of foreign object damage (FOD).
- The engine fragments remained undetected during the first inspection because the request for inspection did not provide specific details regarding the nature or the exact location of the incident.
- The maintenance unit had no reason to perform an unusually thorough search during the first pass, as the request followed standard established practices.
- The engine failure itself was caused by a fracture in the turbine rotor blade, a defect that could not have been predicted using existing engine condition monitoring procedures.
- Environmental factors, specifically runway moisture, likely hindered the visibility of the dark-colored metal fragments during the initial inspection.