Peter Johnson (Flight International, 22-28 April) may be forgiven for coming to his own conclusions based on his assumption that an aircraft with a second engine has a 100% probability of maintaining controllable flight. The evidence shows that this is a false assumption. There continues to be fatal accidents to twin piston aircraft that can be attributed to the failure of one engine.
According to statistics agreed by the UK Civil Aviation Authority in the past 12 years and 3.62 million hours of single-engined turboprop commercial operations, there have been no fatalities due to loss of power. In the UK, the power loss of one engine in a light twin has resulted in a fatal accident rate of four per million, or probably 14 in the equivalent number of hours.
Mr Johnson is entitled to his view that statistics are irrelevant to his immortality. For us mortals operating a single-engined turboprop aircraft, the statistics speak for themselves: old technology piston engines are unreliable. The safety of twin piston aircraft does not come anywhere near that of the new generation of single-engined turboprops.
Peter Wood Gloucester, UK
Source: Flight International
