Smooth Start To Fast-Paced Leap-1A Test Program

By Guy Norris
Source: Aviation Week & Space Technology
October 28, 2013
Credit: CFM

It is ironic that when the first CFM56 fired into life in 1974, barely anyone outside of General Electric or its French partner Snecma noticed or even seemed to care.

It was a low-key debut for an engine that would become an industry game-changer, yet 39 years later the contrast could not be greater for the first run of its 21st-century successor, the all-new Leap. The reason is simple. Compared to the first CFM56, which at the time was an unproven orphan with no applications or orders, the Leap is already a pivotal component of the plans of Airbus, Boeing and Comac. Remarkably, more than 5,000 Leap engines were on order before a drop of fuel was ignited.

The pressure on CFM is therefore intense. Not only does the Leap inherit the vast medium-thrust, high-bypass market dynasty created by the CFM56, it must also maintain from Day 1 the CFM56's mature reliability rate while concurrently improving fuel burn by a step-changing 15%. Just as challenging to GE and Snecma, the large backlog means production is set to start at record rates from the get-go. Delivery rates are set to exceed 1,700 Leap engines per year within just three years.

For the first time since its formation in 1974, CFM is also facing a competitor from the start: Pratt & Whitney's PW1000G geared turbofan. This powerplant not only challenges across a broader thrust range than the International Aero Engines V2500 which it succeeds, but will enter service on the Airbus A320neo ahead of the Leap. Although the Leap and PW1000G only compete head-to-head for the Neo, the engine contest is as cutthroat as ever.

The air of expectancy is therefore almost palpable at GE's test site here in rural Ohio where the first Leap-1A engine is in the early phases of evaluation following its start-up on Sept. 4. The Leap-1A is destined for the A320neo, slated to enter service in 2016, and will be followed by the aero-mechanically identical Leap-1C for the Comac C919, as well as the architecturally common Leap-1B for Boeing's 737 MAX. The C919, the Chinese airliner project that officially launched the Leap in late 2009, is scheduled to enter service in 2017, although CFM is maintaining its original engine development schedule, which calls for the -1C to be certificated in mid-2015. The Leap-1B is on track to enter service on the MAX in 2017.

“The engine is running fantastically,” says Ted Ingling, engineering lead for the Leap-1A/C. Initial work is focused on aero-mechanical engineering tests to look at the high-order attributes of the engine and establish that the “fundamental architecture is working as expected,” Ingling says. “We are making sure the thrust in the rotor architecture is where we want it to be, and to make sure we understand the fundamentals of the engine. We do those kind of tests while we're developing initial software loads for follow-on runs. We use the first engine to tune that software,” he adds.

Staying on track will be critical to the success of the busy test effort that quickly ramps-up before the end of this year and into 2014 when, at one point, up to 15 development engines will be running in parallel. “That is unprecedented and that's only part of the overall test plan,” says CFM Executive Vice President Chaker Chahrour. The overall test and certification program will eventually include 60 engines. Some 28 will be development engines for the Neo, MAX and C919, while the balance is made up of compliance engines which will power the three new airliners during their certification campaigns.

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