FAA Certifies Diesel Auto Engine Conversion

Certification First

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In November the FAA granted type certification to the Thielert Aircraft Engines (TAE) TAE 125-01 four-cylinder 135-hp aviation diesel engine. The model is a diesel automotive engine, made by Daimler Chrysler, which TAE converts for airplane use by adding a gearbox and other aviation-specific parts.

The certification for the engine, known as the Centurion 1.7, is the first of its kind for the FAA. The approval surprised many industry observers because it entailed producing an engine with parts that the manufacturer (Daimler Chrysler) would not verify. But the FAA was surprisingly willing to work within this restriction and allowed Thielert to verify, through a combination of component testing, parts validation, test stand runs, and ongoing testing that the engine, and the parts that make it up, meet an acceptable level of safety.

To our knowledge, the certification of the engine also entails another first, the approval of a powerplant with a time before replacement (TBR) limit-1,000 hours or 12 years, whichever comes first-with no overhaul allowed. When the engine reaches one of those milestones, the owner must replace it with a new engine. The company is working toward a 2,400-hour TBR, and will pro-rate replacement engines from the beginning at the 2,400-hour figure.

Thielert plans to offer an STC for retrofit installations of the engine in Cessna Skyhawks. Diamond is developing its TwinStar light twin around the Centurion 1.7 engine, and OMF is working on a diesel version of its two-place Symphony.