During the conceptual design of the PiperJet, the company conducted several surveys of current and potential customers to find out exactly what they wanted from Piper.
Of course any survey generates a range of responses, but Piper identified a clear desire for a simple, single engine turbofan aircraft. Such an aircraft would be a natural step up from existing single turboprop aircraft.
At the time, the only single turbofan aircraft in wide use were military fighters and trainers, but none in general aviation service. Piper knew there would be a natural question about the operational safety of single engine turbofans, in spite of their excellent safety record with the military, so Piper conducted a detailed analysis of general aviation accident rates in an attempt to predict the safety of single engine turbofans.
Piper reviewed the NTSB’s Aviation Accident Database, specifically in the 10-year period between 1998 and 2007. The engineers also reviewed other reports that attempted to summarize accident trends. What they found confirmed many widely held beliefs, but also included a few surprises.
As expected, turbofan airliners have an excellent safety record, both due to the equipment and the pilot training. Turbofans in general aviation use have better safety records than turboprops with accident rates 50% lower than turboprops.
It was interesting to compare the safety of single and multi-engine turboprop aircraft. Their overall, engine related, and fatal accident rates were very similar. Their fatal engine related accident rates were very low. However, the single engine turboprop aircraft had one-third of the engine related fatal accident rate compared with multi-engine turboprops.
Whether that difference can be attributed to the lower stall speeds and thus lower impact speeds of single engine aircraft or attributed to the reduced pilot workload following an engine shutdown is unknown, but the effect on fatal accidents was clear. Piston powered aircraft showed a similar relationship between single and multi-engine aircraft and their fatal accident rate following an engine related event.
Combining these trends, Piper estimate that a single engine turbofan powered aircraft, like the PiperJet, should have an excellent safety record, on par with twin turbofan aircraft. Single turbofans will likely have overall accidents at a similar rate as their twin turbofan cousins, and there is a strong chance that their engine related fatal accident rate will be even lower than the twin turbofans.
In summary, Piper Aircraft is concerned for the safety of our customers. Unfortunately accidents do happen and the company does everything they can to eliminate the aircraft as being the cause of any future accidents. But after analyzing the data, rather than rumors and suspicions, Piper engineers are confident that the single turbofan PiperJet will be an excellent, safe choice for our customers.
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