What happened
On May 26, 2011, the crew of a Korean Air Airbus A330-300, registration HL7553, was climbing through 11,500 feet when they reported a loud bang originating from the number 2 engine. This was immediately followed by a significant increase in vibration.
Approximately two minutes after the initial bang, the engine exhaust gas temperature on the Pratt & Whitney PW4168A engine rose above 705 degrees. The crew then observed a stall and fire warning. In response, the pilot shut down the engine and discharged one fire extinguisher bottle. The crew performed an air turnback, and the aircraft landed safely with no injuries.
The investigation
A post-flight inspection of the number 2 engine identified a puncture in the Low Pressure Turbine Case, measuring approximately 60 centimeters by 10 centimeters at the 11 o'clock position, along with two small holes. Investigators also found metal fragments within the exhaust and cowling area. There was no damage found to the rest of the aircraft.