Despite its relatively untroubled path toward service entry, the CFM International Leap engine series continues to be dogged by allegations – always strenuously denied – that the narrowbody powerplant is not meeting its performance specifications.
Raising this issue in interviews inevitably provokes visible irritation in its executives.
Allen Paxson, executive vice-president at the GE Aviation-Snecma joint venture, is no exception. Although he displays no anger, there is a sense of slight exasperation when the subject inevitably arises, almost as though he cannot understand why is being asked to repeat himself.
"We are running the engines now on the ground and they are right on specification – and I'm talking 10,000th of a percent. We are right there," he says.
"We are very, very confident. Is it done? No, because we have not delivered [a production engine]. But the engines are drinking the amount of fuel to meet our specification level so we are there."
And just in case the point was not grasped the first time around, he adds: "They have demonstrated specification-level performance: they have demonstrated that on the flying testbed and on the ground. I'm 100% confident that we will deliver specification-level performance."
To some extent, CFM's focus is now shifting from the testing and certification phase – although the latter milestone is still to come on the -1B for the Boeing 737 Max – to service entry.
CFM's first production engines for the A320neo will be handed over to Airbus later in March or in early April, says Paxson, ahead of first customer delivery in the second half of 2016.
Airbus has yet to name which airline will receive the initial Leap-equipped Neo, but Paxson says CFM is working with six to eight customers "who are preparing for entry into service in the second half".
A second Neo delivery should take place around a fortnight after the first, he says, and there are "six customers receiving them in the first three months".
And with the 737 Max due to arrive in 2017, some 50 airlines will be receiving Leap engines over the next three years, he adds.
Paxson describes the Leap-1A as the most successful flight test programme "in our history – either as GE or CFM", having accumulated over 1,340 flight hours on the engines to date across 265 flights. Airbus has been flying the Leap-equipped A320neo "without any interruptions", he says – a nod to the more troubled flight-test phase of the rival Pratt & Whitney PW1100G engine.
The CFM powerplant was also the first engine to fly on the larger A321neo, albeit that its flight-test progress was curtailed after the aircraft suffered a tail-strike in Perpignan in early February.
Nonetheless, that adds to a number of other firsts for the Leap on the Neo programme, says Paxson, such as hot-and-high trials: "All the way through testing we have been really proud that Airbus has been leaning on the Leap engine."
In the coming weeks, specific range tests will be added to the list of milestones, he adds, designed to measure the capability of the aircraft against its performance specification, and, yes, that includes the engines. "I am confident that the engines we have delivered to Airbus are right on specification," he reiterates.
Meanwhile, on the other side of the Atlantic, Boeing is continuing its flight-test regime with the 737 Max 8. As of 22 March, it had performed 60 flights using the Leap-1B-powered aircraft, amassing some 150h of engine testing.
Boeing is flying "as much or more than they expected", says Paxson.
No issues have appeared during testing so far, he says: "It's not by luck, it's because over the last five years we have been testing and retesting. We have had thousands of people working hard to make sure this goes perfectly."
However, despite Max flight testing having commenced in January, engine certification has yet to be achieved, an unusual albeit not-unheard-of situation.
Paxson says that joint approval from the US Federal Aviation Administration and European Aviation Safety Agency is "weeks away", with all tests completed and paperwork submitted. "We would like to think the process would be quicker as they have already been through it on a similar model [for the Neo]," he adds.
"The bottom line," he says, "is that Boeing has what they need to go fly with full confidence and get the airplane ready."
As the flight testing progresses, CFM is continuing its own set of trials to ensure the maturity of its production system when the Leap engine enters service.
Those stress tests – which mimic output 12-18 months in the future – are examining not only CFM's own manufacturing sites but those of its major suppliers and even from the tier below.
"Every sub-tier to our suppliers is critical to the process. It is part of the risk abatement in the build-up," says Paxson.
Output this year is 140 engines, split 50:50 between GE and Snecma's respective facilities in Durham, North Carolina and Villaroche, France. The figure roughly doubles each year, with CFM intending to produce 400 leap engines in 2017, 1,000 in 2018, and then 2,000 in 2019 as it tackles the 10,400-plus backlog across three variants.
"We have not ramped up to these volumes as quickly in our history. We believe that we have the supply chain – between ourselves and Snecma – to do it. We have put a lot of time and effort into getting ready."
That effort is rendered more complicated, however, by the fact that orders for its current CFM56 powerplant, which equips both the A320ceo and 737NG, have stayed strong. The backlog for the engine currently sits at over 3,200.
Last year there were 1,612 deliveries of the CFM56, a record, "and we will break that again this year", says Paxson, with output targeted at around 1,700 units. This will be "peak" production for that model, he says, with production progressively reduced through 2019 until it is only making "a handful a month".
He adds: "We didn't originally plan for 2016 to be the peak; we thought it was 2015. But both airframers – Airbus and Boeing – are going up the rate curve."
Given the backlogs for both engines, the two halves of CFM have been investing heavily in new facilities, opening nine new factories in eight years. In 2015, sites in Rochester, New York and Commercy, France came on stream, and this will be followed this year by the inauguration of a new final assembly facility in West Lafayette, Indiana in the second quarter.
The two partners have also been preparing the Leap maintenance network. However, aside from the announcement of three partner-owned shops in France, Belgium and the USA, little has been revealed. Paxson says the network is intended to be an open one, and agreements are being worked on.
Of course, with the relatively complexity of the engine and its use of exotic materials and processes, concerns have been raised over the potential cost of maintenance.
But Paxson insists the target is to achieve the same level as on the CFM56. "Our durability data suggests we are in line to hit that as well," he says.
Source: Cirium Dashboard
