In-flight engine malfunction and air turn-back - Boeing 737-476, VH-TJY, 120 km south-west of Brisbane Airport, Queensland, on 10 November 2009

On 10 November 2009 at around 1900 EST, a Boeing Company 737-467 aircraft, registered VH-TJY, departed Brisbane Airport, Queensland for Melbourne, Victoria. As the aircraft was climbing through 24,000 ft, the flight crew observed abnormal indications associated with the right engine. The aircraft was returned to Brisbane where it landed without further incident.

Engine disassembly and inspection revealed significant damage to the stage-1 low-pressure turbine (LPT). Analysis of the stage-1 LPT blades showed that some blades had sustained levels of thermally-induced microstructural degradation, which may have affected the creep resistance of the alloy and resulted in the blades being susceptible to failure by creep rupture.

Creep rupture was identified as the likely failure mechanism in previous stage-1 LPT blade failures in this engine type investigated by the Australian Transport Safety Bureau and the engine manufacturer. As a result of this occurrence and at the time of writing this report, the engine manufacturer is revising service bulletin SB 72-1113 to expand the range of blade manufacturing batch numbers that had previously been identified as being predisposed to creep-related failure. Blades in the identified batches are to be withdrawn from service as soon as they are next removed from the engine.