The Australian Transport Safety Bureau (ATSB) reported last month that with 5.5 million flight hours recorded on turbofan engines between 2008 and 2012, only 280 powerplant incidents were recorded, or about one every 20,000 flight hours. Of those 280 occurrences, 98 percent could be classified as low risk; four were classified as medium risk, two as high risk and one as a very high risk. None, however, resulted in any injuries to passengers or crew.
Although the rates were low for the turbofan-powered aircraft group as a whole, there were large variations among individual aircraft models. Three aircraft types in particular–the Boeing 747 classic, the Fokker F28/F100 and the British Aerospace BAE 146/Avro RJ–had far greater rates of powerplant occurrences between 2008 and 2012 than any other aircraft studied. Although these types represented some of the older airframes, there were other fleets of similarly aged aircraft with far lower incident rates.
The ATSB said other operating conditions might need to be considered when estimating engine reliability, including the operating environments, flight cycle number (as opposed to total engine hours), maintenance procedures and the individual reporting practices of each operator.