The latest episode in one of the longest and most successful marriages in civil aerospace got under way on 13 June at an engine test facility near Paris. CFM International fired up for the first time the Leap-1B for the Boeing 737 Max at partner Snecma’s Villaroche site. As the sole propulsion supplier to the programme, CFM has a backlog of over 4,000 engines for the more than 2,000 re-powered twinjets on order, and is continuing a relationship of over three decades, during which the GE/Snecma joint venture has built almost 14,000 CFM56-7 and -3 engines, beginning with the 737-300 in the early 1980s.

The Leap – like the CFM56 – is not, of course, exclusive to the 737. CFM is also pushing on with certification efforts for two other variants of the engine: the Leap-1C version, which will be the only option on the Comac C919, and the Leap-1A, which will compete with the Pratt & Whitney PW1000G on the Airbus A320neo family. While it has enjoyed a monopoly position on the 737 since 1981, CFM’s tussle for market share on the Neo continues its long rivalry with International Aero Engines – in which P&W is a partner – on the Airbus single-aisle family.

The first Leap-1B joins four other Leap engines in the test programme. The -1A powered up on 4 September 2013 and CFM expects to have a total of 20 Leap engines – around a third of them the Boeing variant – in test by the end of the year. By next year, the joint venture will have 30 engines on the test programme across the three variants – 13 of the -1B and 17 in total for the closely related Airbus and Comac versions. Each will undergo five separate blocks of ground testing in France and at GE’s facilities in North America, with the powerplants set to accumulate 40,000 engine cycles by entry into service.

CFM plans to have the Leap-1A certificated by the middle of next year, around a year ahead of the -1B. The lag in the schedules reflects the gap between Airbus’s mid-2016 certification target for the Neo and Boeing’s for the Max in the third quarter of 2017. Comac’s schedule for the C919 is to have it in service by early 2018, although testing on the -1C variant is ahead of the -1B. Allen Paxson, CFM executive vice-president, describes the certification schedule for the three engine variants as “aggressive”, but says it will “wring out any issues and solve them before the engine ever enters a customer fleet”.

So far, the Leap-1A and -1C have notched up 500h and 700 engine cycles, with one of the -1C examples taking a winter excursion to GE’s facility at Winnipeg in Canada to assess its ability to withstand extreme cold temperatures. CFM says this was a year ahead of the icing tests that have to take place for certification, and that they “went very well”. Later this year, a crucial step in the certification process takes place when the -1A/-1C variants will be installed on GE’s Boeing 747 flying testbed in California. The -1B is planned to take to the air for the first time next year, says Paxson.

During the next two months at Villaroche, engineers will run tests on the -1B to verify its mechanical operation, stall margin and “the advanced technologies incorporated in the engine”. These include the woven carbonfibre fan, the twin-annular pre-mixing swirler (TAPS) combustor, ceramic matrix composite shrouds in the high-pressure turbine, and titanium aluminide blades in the low-pressure turbine. After that, the engine will travel to GE’s complex in Cincinnati – CFM splits testing pretty much half and half between France and the USA, depending on availability of facilities and particular capabilities at either site.

The second -1B engine – the first actual certification example – will join the programme around the end of August. The initial development engine, says Paxson, is a very different beast to the production versions CFM will be producing at a rate of over 1,500 a year. “Because of all the instrumentation we put on it – some 1,500 leads – it takes months to build,” he says. Before it was even constructed, CFM had conducted “thousands of hours” of component and rig tests. This “philosophy”, he says, has meant CFM is well prepared for the full engine test programme. “This engine is right where we want it to be,” he says.

Thanks to its exclusivity on the 737 Max, and the 4,500-plus order bank shared by the new Boeing and the A320neo, CFM is set to continue to dominate the narrowbody segment in terms of volume – and indeed the commercial engine market as a whole – with a share around three times that of its competitor. On current trends that is unlikely to change until a game-changing single-aisle aircraft comes along, perhaps in the late 2020s. Its monopoly position on the C919 adds about another 800 commitments.

However, Flightglobal’s Ascend Online database shows that the PW1000G enjoys the edge over the Leap in A320neo orders – at 916 to 840. CFM is quick to point out that there are a further 904 Neo orders for which no engine decision has been announced. “The split at roughly a third, a third and a third [undecided] is what we’d expect and we are looking to a lot of activity later this year,” says the manufacturer. The PW1000G is also boosted by being the exclusive engine on the Bombardier Cseries, Embraer’s E2 family and the Mitsubishi Regional Jet, as well as being the “Western” option on the Irkut MC-21.

CFM will undergo “four years of transition” from the CFM56 to the Leap, with a period of overlap before volume production of the CFM56 stops. The supply chain – both GE and Snecma’s own facilities and second-tier manufacturers – is gearing up for Leap production, and for existing CFM56 vendors it is far from business as usual. “The Leap has several new technologies which the supply chain has been working on for two years,” he says. They include new composite fan blades from Snecma, a new GE facility carrying out 3D printing on fuel nozzles, and ceramic matrix composite materials in the turbines.

“These all involve new manufacturing processes which we have been developing,” says Paxson. “All need to be ramped up for volume production. It’s by no means a simple task, but it’s one we are prepared to take on.” Several facilities have been built, including an assembly plant in Indiana and fan-blade factories in France and New Hampshire. “It’s not just a matter of switching production,” he says. “It’s an enormous scale of industrial activity, involving multi hundreds of millions of dollars of investment. Go to almost any industrial country in the world, and you’ll find a supplier contributing to Leap.”

But as CFM prepares for its industrial Leap, the CFM56 remains a major focus. The first CFM56-3-powered 737-300s were delivered to Southwest Airlines in 1984 and production of the current -7 variant – chosen to power the Next-Generation 737 family in 1993 with first delivery to Southwest in 1997 – is still 1,500 engines a year. CFM recently handed over its 10,000th CFM56-7B, and there are more than 3,100 yet to deliver. Even once the Leap is at full production at the turn of the decade, at 1,800 engines a year, CFM will continue to build CFM56s for spares and military applications. “We expect to be continuing to support the CFM56 to 2040 and beyond,” says Paxson. “We are very excited about Leap, but we won’t turn our backs on existing customers.”

CFM – which celebrates its 40th anniversary this year – remains a curious union. The biggest-selling engine brand employs a tiny number of staff, with engineering, production and backroom activities delicately divided between the two transatlantic partners. Although the Leap, launched in 2008, was its first all-new engine for over three decades, CFM stresses that the CFM56 went through a great deal of evolution in that time. “Even the -7B engines of today are not the same as when we launched the programme in 1997,” says Paxson. “We have continued to invest in that product, and we will be looking to the same levels of investment as we continue forward with the Leap programme.”

Source: Flight International