What happened
On March 18, 2020, a Vietnam Airlines Airbus A321, registration VN-A392, was performing a commercial takeoff from Runway 25L at Tan Son Nhat International Airport in Ho Chi Minh City. During the takeoff roll, while the aircraft was accelerating at a ground speed of approximately 132 knots, the crew heard a loud explosion originating from the right side of the aircraft. The aircraft began to drift toward the right side of the runway.
Following the explosion, the flight crew immediately initiated a rejected takeoff procedure. The aircraft managed to come to a complete stop safely on the runway. Following the stop, the crew followed emergency procedures, which included shutting down the number two engine and deploying the engine fire extinguisher. All 152 passengers and 7 crew members were evacuated via ladder cars and returned to the terminal without injury.
The investigation
The Civil Aviation Authority of Vietnam (CAAV) conducted the investigation, coordinating with the engine manufacturer, the aircraft manufacturer, and international agencies including the NTSB and BEA. Investigators examined the flight data recorder, cockpit voice recorder, and the physical wreckage.
Significant damage was identified on the aircraft, specifically to the number two engine. The investigation revealed that the High Pressure Turbine (HPT) 1st stage disc had fractured, with portions of the disc being thrown from the engine. This failure caused the thrust reverser to tear, the fan cowling to be displaced, and resulted in damage to the aircraft's wing and fuselage structure. Additionally, the engine debris caused damage to the runway surface and broke a window at a nearby weather radar station.
Findings
- The primary cause of the incident was an uncontained failure of the HPT 1st stage disc in the number two engine.
- Metallurgical examinations of the engine fragments suggested a potential manufacturing anomaly within the HPT 1st stage disc.
- The failure of the disc led to the separation of the disc's hub and bore from the inner portion of the disc.
- There were no injuries to the 152 passengers or 7 crew members on board.