CFM International—the 50-50 joint venture between GE and France’s Snecma—has started testing the first full Leap turbofan engine, the company announced Friday. The Leap-1A—one of the powerplant choices for the Airbus A320neo—fired for the first time on September 4, two days ahead of schedule. After a series of so-called break-in runs, the engine ran smoothly and reached takeoff thrust, reported CFM.

The milestone marks the start of a ground and flight test certification program expected to encompass 60 engine builds over the next three years and culminate in engine certification in 2015. Airbus plans to deliver the first Leap-powered A320neo in 2016.

Installed at Site 3B at GE’s Peebles, Ohio, outdoor test facility, the engine will remain “on test” for the next several weeks, said CFM. The overall certification program, which encompasses all three Leap engine variants, includes 28 ground and CFM flight-test engines, along with a total of 32 flight-test engines for the Airbus A320neo, Boeing 737 Max and Comac C919. Plans call for the engines to accumulate approximately 40,000 hours (18,000 engine cycles) during the certification program.