CFM International’s joint owners General Electric and Snecma are preparing for the venture’s biggest transition as it nears milestones for the introduction of its Leap family of engines and increased production rates.

The two tasks will ramp up annual single-aisle engine production to 1,700 units by 2020 from the current rate of 1,450 engines, a 17% increase, and transition production from the current CFM56-5B/7 engines for the Airbus A320 family and the Boeing 737 to the new CFM Leap-1A, -1B and -1C for the A320NEO, the Boeing 737 MAX and the Comac C919.

“Something like this has never been done before,” says Francois Harant, supply chain director at Snecma.

CFM plans a phased Leap engine production from early 2016 and intends to complete the full transition to the new engine family by 2019. CFM expects it will continue to produce about 100-200 CFM56 engines for several years after 2019 to be used as spares.

Airbus has said it may not produce the current A320 series beyond 2018, although no exact timeline has been fixed, and Boeing has yet to publish a phase-out for its 737NG production. CFM says it will build the CFM56 for as long as Airbus and Boeing want the engine.

The 1,700 target assumes monthly production rates of 42 each for the NEO and the MAX in 2019 or 2020, when CFM also expects between 50 and 100 C919s to be built annually.

According to Harant, GE and Snecma will have the capacity for about 2,000 engines; conversely, the engine consortium has contingency plans should CFM56 demand dip ahead of the introduction of the Leap series.

There are no plans to build the Leap in China, although CFM has signed a memorandum of understanding to investigate the possibility, with company officials acknowledging that such a move would only make sense once C919 production has sufficient numbers. Indeed, Harant says there is going to be more production capacity than is needed. “We will use surge capacity to ease the Leap transition, and we are reviewing what has to be added to be more comfortable.”

With the design now frozen for the -1A and -1B versions, CFM is preparing to select the first source suppliers in early 2013 from a pool of 250 suppliers for finished parts and 80 for raw materials. The current CFM56 suppliers are likely to form the overwhelming majority of the Leap supply base, too, but given the introduction of new technologies, new suppliers also will be required.

Second source suppliers are to be added as soon as possible, but CFM opted for a phased approach, rather than selecting all of the partners at the same time. The company, however, already has determined which parts will be produced in-house or purchased.

GE and Snecma are dedicating $750 million in capital investment to the Leap program infrastructure. Blade manufacturing facilities are being built in Rochester, N.H., and Commercy, France, in 2014 and 2015 in order to ensure an output of 34,000 Leap blades per year–there are 18 per engine. The two plants’ layout, machining and tools will be identical.

As part of their efforts to expedite production maturity, the two CFM partners already have produced about 2,000 blades in their existing facilities and are currently building them at a rate of about 50 per month. That will increase to 100 per month by the end of the year.

None of these blades, however, will be used on a production engine. “We continue to learn. It is a brand-new process for us, and we have to be comfortable,” says Harant, adding that CFM is “still adapting blade design based on the test results.”

The composite blades are made by using a new weaving design to withstand bird strikes. Using composites makes the blades significantly lighter than the titanium parts used in the CFM56.