What happened
On July 18, 2006, an Airbus A321, registration OK-CEC, operated by Czech Airlines, was performing a charter flight from Rijeka (LDRI) to Prague (LKPR). During the takeoff roll, the left engine suffered a sudden failure at a speed of 136 knots, which was above the V1 decision speed. The engine failure was accompanied by a loud noise and the release of incandescent metal fragments from the engine core.
These hot fragments struck the runway surface, igniting a fire in the grass area along the left side of Runway 32. The fire lasted approximately 50 minutes, forcing the temporary closure of the runway. Because the takeoff airport was unavailable for a safe landing due to the fire, the flight crew utilized the services of the air traffic controller to divert to the nearest available airport, Pula (LDPL). The aircraft landed safely at the alternate airport, and there were no injuries to the 179 passengers or the crew.
The investigation
The ÚZPLN investigation focused on the mechanical failure of the left engine, a CFM56-5B3/P. The engine was removed and sent to Snecma Services in France for a detailed teardown. Metallurgical analysis of a high-pressure turbine (HPT) rotor blade was conducted at GE Aviation. Investigators also examined the condition of the HPT stator segments, noting that cooling hole contamination can lead to localized overheating and material loss.
Findings
- The primary cause of the incident was the sudden loss of power in the left engine during takeoff due to the failure of a high-pressure turbine rotor blade.
- Metallurgical analysis indicated the presence of a fatigue crack on the trailing edge of the blade near the root.
- The failure of the blade caused extensive secondary damage to downstream engine components.
- The release of hot metal fragments from the engine caused the fire on the airfield grass.
- The flight crew followed standard operating procedures and ECAM protocols, correctly managing the engine shutdown and the diversion to the alternate airport.