CFM Modifications Ease Leap Engine Maintenance Burden

CFM International says it is achieving breakthroughs in ongoing efforts to reduce the maintenance burden for airliners powered by its Leap engines. On Monday, the manufacturer reported that it is increasing the availability of a reverse bleed system that is already on almost half of the Leap-1A turbofans.

The new system prevents carbon build-up on the fuel nozzles by circulating cooling air through the engine core after shutdown. CFM is awaiting imminent engine-level FAA certification of the technology for the Leap-1B model.

To boost what has been a disappointing time-on-wing performance for the engines, CFM has now shipped more than 1,200 durability kits for the Leap-1A’s high-pressure turbine (HPT), both on new-build engines and for fitting during overhauls. The GE-Safran joint venture claims the new hardware helps to increase the time between shop visits, resulting in a two-fold improvement in time-on-wing in severe environments and achieving comparable reliability rates to the widely used CFM56 engines.

According to Gaël Méheust, president and CEO of CFM International, these initiatives are especially important for operators in the Middle East, where fine desert dust suspended in the air builds up in the cooling passages of engines, shortening the life of components. “With more than 17,000 cycles of Leap dust testing to date, we’re confident that the design we’re delivering today is the hardware we’ll need to meet our customers’ expectations for time on wing,” he commented in an interview before the Dubai Airshow.

While acknowledging that there is more work to do in maturing the Leap program's reliability, Méheust insisted that his engineering team is making progress. He pointed to Cirium data showing that over the past 12 months, airliners powered by Leap engines have flown 25% more days than narrowbodies powered by the alternative Pratt & Whitney Geared Turbofans.

At the same time, CFM said it is increasing production rates for the Leap engines, which it said were up 40% year over year in the third quarter. Méheust said he expects Leap deliveries for the whole of 2025 to be 20% higher than the 2024 output.

CFM56 Improvements, Rise Testing

More than 30 years after the first CFM56 turbofans entered service in the narrowbody market, the engine maker said it remains committed to increasing their value to operators by lowering ownership costs. In late 2023, it introduced a more durable HPT blade to extend time on wing and has already shipped more than 1,700 sets of the hardware.

“As with Leap engines, though, the more repairs we can do, the fewer spare parts we need, and the lower the maintenance cost,” Méheust explained. “That’s why we continue to industrialize new repairs. For example, by rolling out automated laser welding, we’re increasing part throughput and decreasing repair turnaround time for the prior-generation HPT blade by about a third.”

Meanwhile, CFM’s next-generation Rise engine is continuing its path to market, with more than 350 different types of tests completed to date, including assessments of its Open Fan architecture, compact core, high-speed turbine and compressor, and hybrid-electric systems. The company is striving to deliver a 20% reduction in fuel burn and CO2 emissions compared to today’s engines.

In October, dust ingestion tests began on Rise’s HPT airfoils, which CFM said is the earliest in any of its programs that it has conducted this level of real-world testing. Earlier this year, it completed more than 3,000 endurance cycles with the HPT airfoils.