What happened
On 26 May 2011, a Korean Air A330-300, registration HL7553, was climbing through 11,900 feet near Incheon International Airport when the crew experienced a sudden bang and an uncommanded right roll. This was immediately followed by a No. 2 engine fire warning, accompanied by continuous chimes and high vibration and exhaust gas temperature alerts.
The flight crew promptly executed emergency procedures, shutting down the No. 2 engine and discharging the fire extinguisher. After confirming the fire warning had ceased, the crew declared an emergency and performed an air turn back to Incheon, where the aircraft landed safely via an ILS approach. There were no injuries among the 281 passengers and 14 crew members.
The investigation
The ARAIB conducted a detailed examination of the engine hardware and flight data. An engine teardown revealed significant internal damage, including the destruction of all 7th-stage low pressure turbine (LPT) blades and vanes. Investigators found a hole punctured through the LPT case at the 9 o'clock position, with metal fragments found near the exhaust nozzle and damage to the wing flap track moving fairing.
Technical analysis focused on the 4th-stage LPT vane clusters. The investigation examined the hardware at both the airline's maintenance facility and Pratt & Whitney's specialized facilities to determine why the engine components failed.