CFM International at 50: Sharing everything - how CFM engines are produced

The very idea of CFM International might, on the surface, seem an unlikely proposition. The world’s most prolific aero propulsion business – it has delivered more than 42,500 engines – has assembly lines and engineering departments on both sides of the Atlantic. Meanwhile, GE Aerospace and Safran Aircraft Engines each run separate supply chains, and their sales teams manage their own relationships with customers.

In fact, CFM’s structure is incredibly straightforward – and little changed from the principles founding fathers René Ravaud of Snecma and GE’s Gerhard Neumann hammered out more than 50 years ago. The premise – then and now – is that the two parents share everything, from design and development to production and aftermarket strategy. Customer contract terms are agreed by both partners and revenues split down the middle.

In fact, the only aspect of the partnership that is never shared is costs. While executives and engineering teams at GE Aerospace and Safran Aircraft Engines are by necessity open with each other about technology development and supplier relationships, terms with those suppliers are not disclosed, and neither are each company’s other internal outlays.

GE Aerospace and Safran Aircraft Engines are each responsible for – and own the intellectual property rights to – their own technologies within the engine. The US company develops and builds the core, comprising the high-pressure (HP) compressor, HP turbine, and combustor, while its French counterpart owns the fan, accessory gearbox and low-pressure (LP) compressor and turbine.

Because each parent pays its employees – some of which are effectively seconded to CFM – as well as its properties and equipment (the joint venture does not have its own staff or assets to speak of), CFM is a ‘revenue business’. The money it makes from customers is divided two ways and feeds straight through to the revenue line in the accounts of its two shareholders.

There are three final assembly lines for CFM engines, at GE Aerospace in Lafayette, Indiana and Durham, North Carolina, as well as Safran Aircraft Engines’ facility in Villaroche, France. LEAP-1A engines for Airbus aircraft are assembled in France, while the US plants are responsible for their LEAP-1B counterparts – a similar arrangement applied to the CFM56. Villaroche also assembles COMAC’s C919 LEAP-1C engines.

While the split keeps production numbers roughly equitable between the two partners, all three facilities can produce every version of the LEAP engine with slight tweaks to the assembly process. As Boeing 737 MAX output ramps up, the French factory may complete some LEAP-1B final assembly.

At the sub-system integration level, GE Aerospace assembles the elements of the engine core for all variants, and ships those destined for LEAP-1A and LEAP-1C powerplants to Villaroche. Safran Aircraft Engines performs a similar role on the fan and LP sections, transporting the assembled LEAP-1B stages it is responsible for to the US.

A host of GE Aerospace, Safran Aircraft Engines and supplier manufacturing sites support the LEAP programme, most of them in the US and France, but also in the likes of Belgium, Brazil, China, India, Malaysia, Mexico, Morocco, Poland, and Singapore. Notable suppliers include GKN Aerospace, with which Safran Aircraft Engines signed a 10-year agreement earlier this year covering shaft production and support, initially on LEAP-1A variants.

The transition to the LEAP engine in the second half of the previous decade – at a time Airbus and Boeing were rapidly increasing single-aisle production – meant CFM had to start planning from when both manufacturers selected the engine. By early 2015, the backlog for LEAP engines, at around 8,700, was more than twice that for the CFM56. However, output of the new engine was, at that point, still in very low volumes.

CFM faced the challenge of ramping up production of the new engine to more than 1,900 by the time the decade was complete, while still maintaining (robust but declining) output of its predecessor. The LEAP engine’s novel technologies – such as the three-dimensional woven fan – meant new supply sources had to be found, while sheer volumes meant upgrades and expansions of existing sites were necessary.

Complex technologies

The ramp-up of the LEAP engine was different to that of previous CFM56 updates, such as the -7B, because of newer, more complex technologies. It meant careful nurturing of a supply chain, which, although most had worked on the CFM56, was still often making baby steps with advanced materials including resin transfer moulded (or RTM) fan blades, titanium aluminides, coatings, alloys, and ceramic-matrix composites (CMCs).

In terms of the partners’ own infrastructure, a new 21,000sq m (225,000sq ft) final assembly line was opened in Lafayette, while a second Boeing 747 flying testbed was commissioned for the GE Aerospace flight test site at Victorville, California. In total, more than 8,000sq m of space was added to GE Aerospace sites to get ready for LEAP engine production.

Meanwhile, at Safran Aircraft Engines, with a requirement for 32,000 new-style fan blades a year by the end of the decade, facilities to manufacture the RTM products run by Albany Engineered Composites were added in Commercy, France and Rochester, New Hampshire. Each was sized to employ around 400 production staff.

Despite its success, CFM’s concept has never been replicated in the industry. There have been engine collaborations aplenty – from GE Aerospace’s with Pratt & Whitney to develop the Engine Alliance’s GP7200 for the Airbus A380 to Safran’s shareholding with Rolls-Royce and others in Europrop International, which makes the A400M engine. However, the clean and lean simplicity, not to mention success and longevity, of CFM sets it apart.

No one at CFM takes future prosperity for granted. Despite the venture’s impressive track record, a current backlog of more than 10,000 engines, and demand for flying set to reach unprecedented levels, there are challenges aplenty. These range from helping a supply chain get back to strength after the Covid disruption, and the need to constantly innovate to stay ahead of competitors and demanding industry sustainability goals.

However, in these times, spare a thought for the 1970s predecessors of today’s engineers and executives at GE Aerospace and Safran Aircraft Engines, tasked with collaborating on a cutting-edge engine design despite being an ocean, six time zones, and a language apart – with the fax machine barely in its infancy, and mobile phones, computer design software, video conferencing, and the internet still things of science fiction.

What they achieved in a different era laid the foundations for CFM’s resounding performance to date, and the promise of an even brighter tomorrow.