Flight Design has begun production on its conforming prototypes of its new C4 aircraft and has expanded the flight-test envelope of the non-conforming model as the manufacturer works toward its first certified product. Germany-based Flight Design is hoping to achieve EASA CS-23 certification for the four-place general aviation aircraft next year, with validation from the FAA following after that.

The proof-of-concept first flew April 9 at Kamenz airfield (EDCM) in Germany, testing basic handling, trim, spiral stability and go-arounds. Primary parameters of the Continental IO-360-AF alternative-fuel engine also were confirmed, the company said.  Since then, the aircraft has completed about a dozen flights, expanding weight and center-of-gravity envelope to establish the baseline stall speed at gross weight. The piston single has flown at 2,640 pounds, demonstrating a stall speed of less than 54 knots. More stability and performance testing are planned over the next few months.

Flight Design’s work has continued through the government-industry consortium on the safety box for the aircraft, which adopts some of the crashworthiness concepts from the automobile industry to build a “safety cage” around the occupants. Flight Design USA president Tom Peghiny, who is directing the flight-test program, said the proof-of-concept incorporates some of the safety box features, but the conforming prototypes will be fully equipped with the design.

The company plans to use three conforming prototypes in the flight-test program, the first of which is expected to fly by year-end.

Plans call for the aircraft to be assembled in the U.S., where 60 percent of its parts are produced, as well as in China, Peghiny said. The company currently is looking at several U.S. locations for assembly but is not ready to discuss those possibilities, said Peghiny.

In China, the company already has begun production on Flight Design’s non-certified CTLS two-seat aircraft, and its plant in Xiamen, China, just underwent audit from the Chinese CAAC aviation authority. This will clear the manufacturer to begin shipment of the light-sport CTLS in China later in the quarter. Flight Design is teamed with Taiwan-based GSEO on its Chinese subsidiary, which operates under the AeroJones Aviation name.