Myth of the Single Engine Aircraft

With Two Engines You Have Twice the Chance of One Quitting...

     The idea that certain companies will not award contracts to bids or proposals with single engine aircraft is based on a myth. The concern is that a single engine would quit and kill their passengers, while twin-engine aircraft have a second engine to pull you out of the death grip that awaits all heedless company managers. In reality, however, piston twin engine aircraft had more accidents than did piston single engine aircraft. Let’s face facts; there is twice as much chance for one of the two engines to fail than if you only had the one. That in it self was not the problem, because the logical conclusion to that argument would be that a 747 is dangerous because you have four times as much chance of having an engine failure.
     The problem was when you had two engines many companies would push the maintenance and rebuilding envelopes to the breaking limits, because, the managers would reason, “you had two instead of only one.”
     Then of course, with two engines you could carry more of a load, not withstanding the POH, because, well….you could. More power and bigger payload was often the justification for buying a twin engine aircraft. Of course the weight and balance would go out the window, but “what the hell” the carriers made more money. “Move over Mr. VP of BP, we have several bags of cement to carry to the work site. You won’t mind will you”?
      Lets recapitulate. One, statistics are on the side that with two piston engines you have TWICE the chance of having one of the engines fail. Two, the maintenance department would extend the TBO’s and service intervals, with the reasoning that with two over-extended engines are safer than one well maintained engine. Three, with more power the operators could overload the twin engine aircraft until they performed much worse when the statistically doomed engine would fail, than a properly loaded single engine aircraft would. Thus the piston engine twins were falling out of the skies quicker than you could say, “buttered bricks.”
     Consequently, someone coined the instructional phrase, “If you lose one engine, pull the good one otherwise she will just take you to the scene of the accident quicker.”
      Worldly-wise Nabil Haqui of Aero Contractors says, “Guns don’t kill people, people do!” He continues to say, “Of course any piston twin would be safer than a single if the operators flew within the confines of the POH and the manufacturers limitations."
     And, may I add, “did all maintenance with the consciousness of knowing that your passengers were going to have to rely on that one engine one day to perform like it was the only engine.” But, the reality is that the operators happily pulled the trigger.
      The “wish they could fly by the numbers” ex-military aviation managers of BP, Texaco, Shell and others, would award that contract accordingly “by the book,” dooming themselves to the myth that precludes the modern cost effective class of aircraft that are revolutionizing the general aviation world.
      The class I am referring to of course includes such state of the art aircraft as the Cessna Caravan and the Pilatus PC-12.  The fact is, consequentially, that such turbine single engine aircraft are much safer than the piston twin engine aircraft, which made a farce out of BP’s guidelines for awarding contracts based on the number of engines rather than the overall safety of the aircraft. I realize that these companies would not award contracts to piston powered aircraft over turbine powered, but the idea of not considering the single engine turbine aircraft is based on faulty logic.

Article and Images by John S Goulet

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Last modified on March 05, 2006 .
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