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Single Turbine Engine Aircraft
Is Two safer than One? No!

Overall Fatal Accident Rates

enhanced education, training and awareness. This period is also relatively historic and for these reasons a previous study 2 considered 1991-2004 more relevant to current and future operations.

On this basis, the updated figures for the data used above, but for 1991 to 2005 inclusive are given below:

3. Discussion

The most recent and relevant accident data indicates an overall FAR of 3.79 per million hours for commercial operations, an improvement since the last analysis a year ago of 11%. The data is dominated by US operations. The US requirements have no engine reliability rule, whereas ICAO, Canada, Australia and other countries, as well as the JAA proposals, require a high level of engine reliability (a Loss of Power Rate of less than 1 in 100,000 engine hours). The ICAO and JAA also require a range of equipment and systems to be fitted and stipulates enhanced operating and maintenance standards, and enhanced crew experience and training. All of this is obviously aimed at improving safety and it can be anticipated that the accident record for aircraft operated to JAA standards should reflect this in lower accident rates.

4. Conclusions

4.1 The overall Fatal Accident Rate in commercial operations for Single-Engine Turboprops based on the latest data is 3.79 per million hours (compared to a JAA target of 5).

4.2 The more stringent requirements in the JAA proposals relative to the US rules (relevant to most SET operations to date) gives the prospect of lower accident rates for JAA approved aircraft.

References:

1. SETA Report RA/2005/02, Issue 4, 3 November 2006: ‘Single-Engine Turboprops: Loss of Power Events’.

2. SETA Report RA/2004/02, Issue 1, 15 March 2004: ‘JAA NPA-OPS-29: Relative Accident Rates for Single-Engine Turboprops and Comparable Light Twins’.