On 11 November 2012 an Emirates A380 departed Sydney Airport for Dubai, United Arab Emirates. While climbing through an altitude of approximately 9,000 feet the crew heard a loud bang accompanied by an engine No 3 exhaust gas temperature over-limit warning. Shortly, thereafter, the engine went through an uncommanded shutdown. The crew jettisoned fuel and returned to Sydney where the aircraft landed safely.
The investigation found that the increase in exhaust gas temperature and subsequent engine shutdown was the result of significant internal damage that had initiated within the high pressure turbine (HPT) module. The damage resulted from the effects of stage-2 nozzle distress likely caused by exposure to hotter than expected operating temperatures. The nozzle distress had led to eventual failure and separation into the gas flow path. Over the preceding weeks two other engines within the operator’s fleet had been similarly affected.
While the distress to the HPT was severe enough to result in an in-flight engine shutdown, the associated risks to the continuation of the flight were relatively low...
The engine had operated for a total of 15,318 hours and 1,876 flight cycles since new. Of that, 6,748 hours and 793 flight cycles had accumulated since the last workshop visit. At the time of the occurrence there were no outstanding items on the engine’s maintenance log. During the preceding flight of the aircraft, the manufacturer’s engine health and trend monitoring program had identified a performance trend shift with this particular engine and it was due to be inspected on return to the main base in Dubai.
The engine’s manufacturer, Engine Alliance had issued a service bulletin in June 2010 for the replacement of affected stage-2 nozzle segments with new more durable components during the next workshop visit when the HPT stage-2 was removed from the engine. Following this occurrence, another service bulletin was released on 6 December 2012, requiring the direct inspection of the nozzle segments that had not been replaced. The US Federal Aviation Administration also released an Airworthiness Directive that required inspection of the nozzle segments and their removal from service if distress was identified.
While the distress to the HPT was severe enough to result in an in-flight engine shutdown, the associated risks to the continuation of the flight were relatively low, given the failure had been contained and the operators procedures were effective in managing the shutdown. This occurrence pointed to the value of real-time engine condition monitoring since advanced warning of engine degradation and efficiency loss allows inspection and corrective action to be taken before damage progresses to cause a shutdown.
Read the report: Engine failure involving Airbus A380, A6-EDA, near Sydney Airport, New South Wales, on 11 November 2012