On 23 May 2015 an Airbus A330 was flying from Singapore to Shanghai, China. When the aircraft was about 130 NM to the south-east of Hong Kong and cruising at 39,000 feet, it encountered an area of adverse weather.
To avoid areas of higher weather cell intensity the flight crew turned to 020 degrees and prepared the aircraft for possible turbulence by turning on the seat belt sign and other precautionary measure.
Crew turned on the wing anti-ice and selected continuous ignition for both engines.
Subsequently the aircraft entered a weather cell and the engines experienced surges.
The aircraft’s Electronic Centralised Aircraft Monitoring (ECAM) displayed a message indicating that Engine No. 2 (the right engine) had surged, Before the flight crew took action, the right engine had self- recovered from the surge, but the ECAM message was replaced by another ECAM message indicating that the left engine had surged.
The flight crew declared Mayday to ATC and then shut down Engine No.1. With only one engine functioning normally, it would not be possible to maintain a cruise at 39,000 feet. So the flight crew, with ATC’s clearance, descended the aircraft to a cruise level of 26,000 feet.
The crew noted, diverting to Hong Kong or Guangzhou would involve flying through weather cells again, so decided to continue to proceed to Shanghai.
Engine surge time
Flight Data Recorder (FDR) showed the Engine surge occurred for 12 seconds, Engine No. 2 surged three times and Engine No. 1 two times, and Engines No.1 and No. 2’s first surges occurred at about the same time at 12:56:56 hours, which was about 22 seconds after the aircraft’s left turn to a heading of 020 degrees.
There was a significant amount of grey coloured dust deposit found on the aerofoil surfaces of some Intermediate Pressure Compressor (IPC) rotor blades and stator vanes, on the Intermediate Pressure Turbine (IPT) nozzle guide vanes and on the High Pressure Turbine (HPT) stubshaft (see Figure 1). The dust was identified to be composed mainly of aluminium and silicon, which were the main constituents of the IPC rotor path abradable material.
There was heavy rubbing at Stages 3, 4, 5, 6 and 7 stator vane shrouds. The rubbing could be attributed to contacts with the air seals of the IPC rotor drum (see Figure 2).
The investigation team believed that the engine surge in Engine No. 1 was most likely a result of the release of IPC rotor path abradable lining material. Although Engine No. 2 was not disassembled and examined, the investigation team believed that Engine No. 2, being as new as Engine No. 1, experienced the engine surge for a similar reason.
The aircraft manufacturer has enhanced its Flight Crew Training Manual Section FCTM-AO-70 to provide the following information:
A brief description of an engine stall
The possible causes of an engine stall
The different symptoms of an engine stall
The procedure associated with an engine stall
The operator has adopted a policy not to pair new engines on A330 aircraft. New A330 aircraft that are delivered with new engines will have one of the engines replaced by a relatively older one.