The ATSB has been advised that the hours flown data provided by the Bureau of Infrastructure, Transport and Regional Economics (BITRE) and used for the calculation of occurrence rates by aircraft type, may have been under-reported for some aircraft types used in charter operations. The ATSB is awaiting new hours flown data from BITRE and will update the reports accordingly when this data is available.
Why the ATSB did this research
This is the first in a series of research investigations looking at technical failures reported to the ATSB between 2008 and 2012. This report reviews power plant problems reported to the ATSB affecting turbofan-powered aircraft, and the types of incidents they are associated with.
By summarising power plant-related occurrences across all operators, this report provides an opportunity for operators to compare their own experiences with others flying the same or similar aircraft types, or aircraft using the same engines. By doing so, the ATSB hopes that the wider aviation industry will be able to learn from the experience of others.
What the ATSB found
Despite the complexity of modern turbofan engines, their reliability is evidenced by the remarkably low rate of power plant occurrences. With a combined total of over five and a half million flight hours for turbofan engine aircraft between 2008 and 2012, there were only 280 occurrences relating specifically to the power plant systems (or approximately one occurrence every 20,000 flight hours). Additionally, the vast majority of these (98%) were classified as being a low risk rating occurrence with a low or no accident outcome. Only four were classified as medium risk, two as high risk and one as very high risk. None resulted in injury to passengers or crew.
Although the rates were low for the turbofan engine aircraft group as a whole, there were large differences between 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 power plant occurrences between 2008 and 2012 than any other aircraft in this study. Although these three aircraft types represented some of the older fleets, there were other fleets of aircraft of similar ages with far lower rates of occurrences.
The small number of high and very high risk power plant occurrences between 2008 and 2012 remind us that even highly sophisticated modern power plants can, and do, fail. Timely and vigilant reporting of all technical problems is therefore strongly encouraged to ensure as much information as possible is collected to better understand these problems. Of particular importance in technical occurrences are the follow-up reports from engineering inspections. These are often the only way that the root cause of the problem can be determined. The more comprehensively these are reported to the ATSB, the more insightful and useful reports like this become.