Story ID: 385
CFM Certifies Leap 1B Engine Durability Kits
By: Charles Alcock
Caption: Engine maker boosts high pressure turbine and fuel nozzle reliability on 737s
Word Count: 570
CFM International has completed FAA and EASA certification of a high-pressure turbine (HPT) durability kit for the Leap 1B engine and expects these to be delivered with new production turbofans from early 2027. At a press briefing in London on Sunday, the manufacturer also reported that during the second half of this year, it expects to complete approval for a reverse bleed system (RBS).
According to Tom Levin, vice president for CFM commercial programs, the modifications are a key aspect of efforts to increase time on wing for Boeing 737 Max operators. The HPT kit is already installed on around 40% of the Leap 1A engines that power the rival Airbus A320 narrowbody, and 70% have the RBS, which cools fuel nozzles to reduce coking on these parts.
Levin told reporters that these two improvements are responsible for delivering as much as 80% of the targeted improvement in engine durability. CFM expects the remainder to be delivered through other innovations, such as a foam wash process for the engines.
The HPT durability kit is especially important for airlines in the Middle East and India, where hot and dusty conditions undermine operational reliability. The RBS cooling system is expected to reduce the frequency with which Leap fuel nozzles need replacing to the standards already achieved with the earlier CFM56 turbofans.
At the same time, CFM joint venture partners Safran and GE Aerospace are making further investments to sustain increases in Leap production rates. In 2025, the OEM delivered more than 1,800 turbofans, representing 25% more than the year before. CFM president and CEO Gaël Méheust wants the company to sustain the improvements at a rate of 15% each year through the end of the decade.
MRO Investments 
As part of the push to boost customer support, GE Aerospace has committed to $1 billion in investments over five years, with Safran Aircraft Engines committed to a similar amount. Questioned about comments in June by IATA director general Willie Walsh accusing engine makers of MRO price gouging, Méheust said that CFM has purposely encouraged an open market for customer support with a growing network of independent providers.
The OEM has recently added new Premier MRO shops, including MTU Maintenance in Texas earlier this month, Iberia in Spain, and SSAMC in China. It no longer offers power-by-the-hour programs to airlines as a way to spread the cost of maintenance.
Five years on from launching its Revolutionary Innovation for Sustainable Engines (RISE) new-generation engine initiative to exploit open rotor technology, CFM reported that it has completed around 500 test campaigns covering features such as compact core modules and the hybrid-electric system that will serve as an engine starter while also stabilizing the operation of the engine’s two shafts. The group is now focused on mechanical and material tests on open-fan blades and outlet guide vanes, including impact, ingestion, fatigue, endurance, load, icing, and vibration response.
With the RISE preliminary design review now complete, CFM says it is on track to start ground tests with “representative-size equipment” before the end of the decade using a core engine of around the same dimensions as GE’s Passport business jet turbofan. Its long-term objective is to have a certifiable engine available from the mid-2030s, with production timing hinging on the still-unresolved questions of when and how Airbus and Boeing may bring next-generation narrowbodies to market.