When modern aerodiesel engines made their surprise appearance at the Berlin Airshow in 2002, the numbers didn’t add up once the costs ultimately came to light. The engines were certainly economical, but they were twice as expensive as gasoline engines, had half the TBOs and required pricey gearboxes and other components at short-run hours intervals. A decade and a half later, these automotive-based engines may finally be turning a corner of sorts, with the announcement by Continental Motors last spring that its CD135/155 series engines will have replacement intervals increased to 2100 hours from 1500 hours.
Although this dramatically improves the operating economics of diesel engines against their gasoline counterparts, it’s not yet clear if that will be enough to expand the market much. Initial indications based on our interviews are that it will not, at least for the short term, simply because new airplanes are so expensive and conversions similarly require large investments.