Factual Information
On 16 May 2011, at about 0112 hours local time, an Airbus A330-343, registration B-HLM, operated by Cathay Pacific Airways, departed from Singapore Changi Airport on a scheduled passenger flight to Jakarta. The aircraft carried 149 persons on board. While climbing through 33,000 feet at 0129 hours, the No.2 engine stalled, accompanied by a loud bang and severe airframe vibration. The flight crew shut down the No.2 engine, reducing vibration but not eliminating it.
At approximately 0145 hours, when the aircraft was descending through 10,500 feet, the No.2 engine fire warning activated. The crew discharged one fire extinguishing bottle, which cleared the warning temporarily. After 69 seconds, the warning reappeared, and a second bottle was discharged. The warning light then flickered intermittently for the remainder of the flight.
The aircraft landed on Runway 02C at 0157 hours and stopped on Taxiway E5. Airport Emergency Service (AES) personnel observed fire on the No.2 engine and extinguished it with foam. No injuries occurred.
Aircraft Damage
Inspection revealed that a 130 mm tip section of one fan blade had separated from the No.2 engine. The interior of the fan case was damaged by rubbing from the unbalanced rotating assembly. The Kevlar wrap of the fan case was ignited by heat generated from the severe rubbing, causing fire damage to accessories on the right side of the engine. The fuel line also sustained damage.
Investigation Findings
The Air Accident Investigation Bureau of Singapore classified the occurrence as a serious incident. The engine vibration resulted from the loss of the fan blade tip, which unbalanced the rotating assembly. The fan blade failure was attributed to its mechanical strength having been compromised by the use of an incorrect gas during the manufacturing process. The subsequent rubbing of the unbalanced assembly against the fan case generated sufficient heat to ignite the Kevlar wrap, leading to the engine fire.
Probable Cause
The failure of the fan blade was attributed to its mechanical strength having been compromised as a result of the use of an incorrect gas during the manufacturing process. The severe rubbing of the unbalanced rotating assembly against the fan case generated heat that ignited the Kevlar wrap, causing the engine fire.
Safety Actions
The engine manufacturer issued service bulletins, and the European Aviation Safety Agency released airworthiness directives. The airport emergency service voice recording system was also improved.
*Note: All times are Singapore local time (UTC+8).*