What happened
On the night of 3 July 2017, an AirAsia X Airbus A330, registration 9M-XXT, was preparing for a scheduled passenger flight from Gold Coast Airport to Kuala Lumpur. The aircraft was carrying 345 passengers and 14 crew members. During the takeoff roll on runway 32, the aircraft experienced increased vibrations in the number 2 engine as it approached rotation speed.
As the aircraft climbed through approximately 2,300 feet, the crew received an engine stall alert accompanied by loud banging noises. Shortly after, as the plane reached 4,000 feet, the engine failure alert was triggered. Simultaneously, the cabin purser notified the flight deck of a visible fire in the starboard engine, which had been observed by a passenger. The flight crew executed emergency procedures, including the discharge of the fire suppression system, and declared a MAYDAY. The aircraft diverted to Brisbane Airport, performing an overweight, single-engine landing on runway 01 without further incident.
The investigation
Investigators from the ATSB and airport operators recovered bird remains and engine debris from runway 32. While two birds were found on the runway, veterinary analysis suggested these specific birds were not ingested into the engine. However, subsequent a detailed engineering examination of the Rolls Royce Trent 700 engine in Hong Kong used ultraviolet light to identify organic debris. DNA analysis confirmed that the debris on the damaged fan blade was from a masked lapwing.
The investigation established that the impact of the bird caused a small section of a fan blade tip to fracture and release. This loss of material created an imbalance, leading to high vibrations that caused the fan rear seal to break and fragments to enter the engine core. This resulted in compressor stalls and a subsequent oil leak. The leaking oil ignited due to frictional heat, creating the fire observed by the crew.
Findings
- The primary cause of the engine failure was a birdstrike involving a masked lapwing during the takeoff roll.
- The specific combination of aircraft speed, engine speed, and the angle of the bird's impact created a rare scenario that led to the release of the blade tip.
- The loss of the blade tip caused an engine imbalance, which subsequently led to mechanical failure of the engine seals and an internal oil fire.
- The flight crew effectively managed the emergency and successfully diverted the aircraft to a safe landing.