When CFM International announced the Leap engine in 2008, it was indeed a leap of faith. As with the launch of the original CFM56 in the 1970s, the General Electric-Snecma joint venture sanctioned the go-ahead of the all-new engine despite having no customer and no firm contract.

Yet, just as with the CFM56, the partners were certain the market for Leap was there; it was simply a matter of time—and timing. Unlike the CFM56, which got its big break on Douglas DC-8 and Boeing KC-135 re-engining deals while still seeking its first twinjet application, the Leap market was always going to be primarily the next generation of Airbus and Boeing narrowbodies. The initial version of the engine, the Leap-1A, which fired up for the first time at GE's Peebles, Ohio, test site on Sept. 4, is designed for the Airbus A320neo.

There are other differences, too. Since ushering in the modern age of the high-bypass-turbofan-powered, single-aisle twin airliner, the CFM56 has racked up orders in excess of 28,000 engines, making it the best-selling commercial turbofan ever developed. Now, not only must the Leap live up to the promise and expectations of its illustrious forebear, but for the first time in CFM's history, it also enters the market with a modern competitor already launched and in advanced development. In this case, the Leap must do battle with Pratt & Whitney's PW1100G geared turbofan, which was given the green light on the A320neo ahead of the new CFM engine.

Based on an all-new core and incorporating a two-stage, high-pressure turbine in place of the single-stage unit that distinguished the F101-derived military core of its predecessor, the hallmarks of the Leap include a larger diameter, composite fan and fan case and advanced materials, such as ceramic matrix composites in the turbine. Compared to the current CFM56-7B, the engine is targeted at 15% better fuel efficiency, 50% lower emissions and noise levels compliant with International Civil Aviation Organization Chapter 5 standards, while retaining the same reliability and maintenance costs as today's products.

Despite the challenges, the Leap is off to a good start. Following its launch by Comac as the sole engine choice for the C919 in 2009, Airbus followed in 2010 when it selected the Leap-1A engine as an option along with the PW1100G. In 2011, Boeing selected the Leap-1B as the sole powerplant for the 737 MAX. Overall, CFM booked firm business for almost 5,450 units even before the first engine started up.

Rated at 33,000 lb. thrust, the first run of the Neo engine marks the start of a fast-paced test and certification program involving 60 test engines for the 1A and other variants.

“Over the next several weeks, the Leap-1A will undergo operability testing, component mapping and power calibration, in addition to validating clearances,” says the engine maker.

In early 2014, the second build of the engine will begin icing tests at GE's facility in Winnipeg, Canada. Around September 2014, the engine is also set to begin flight tests on GE's Boeing 747 flying testbed. FAR33 engine certification is expected the following summer. First flight on the A320neo is due around the third quarter of 2015, and entry into service the following year.

Detailing the various test engines that will be involved in the overall certification program, CFM says this will include 28 ground- and flight-test engines, along with a total of 32 flight-test engines for Airbus, Boeing and Comac. Over the next three years, the engines will accumulate approximately 40,000 hr. (18,000 engine cycles) leading up to entry into service, CFM adds.