ISTAT Online

Appraisal: CFM LEAP-1B

Photo Courtesy of CFM International

Formed in September 1974, CFM International is a 50/50 joint venture between GE Aerospace and Safran Aircraft Engines. Building on the success of the most populous CFM56 commercial engine family, the CFM LEAP engine program was launched as the LEAP-X in July 2008. An eight-year research and development roadmap was outlined, with engine certification anticipated in 2016. GE Aerospace would assume development responsibility for the engine core, including the high-pressure compressor, high-pressure turbine (HPT) and combustor, whereas Safran Aircraft Engines would be responsible for the fan, low-pressure turbine and accessory gearbox.

Subsequently, the CFM LEAP-1C was announced as an engine option for the COMAC C919 in December 2009. This was followed by the announcement of the CFM LEAP-1A as an engine option for the A320neo in December 2010, and lastly, the LEAP-1B as a sole engine option for Boeing’s 737 MAX in August 2011. CFM LEAP-1A certification was jointly awarded by the Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) in November 2015. Certification for the CFM LEAP-1B and CFM LEAP-1C occurred during May and December 2016, respectively. CFM LEAP-1B engines have their final assembly line in the U.S. at GE Aerospace facilities in Lafayette, Indiana, and Durham, North Carolina; both LEAP-1A and LEAP-1C final assembly is completed at Safran Aircraft Engines’ facility in Villaroche, France.

Engine Thrust Ratings

To date, Boeing has achieved certification for its MAX 8, MAX 8 200 and MAX 9 aircraft within its Boeing 737 MAX aircraft family. Basic engine thrust ratings for the MAX 8 and MAX 8 200 are 25,000-pound force (lbf) (LEAP-1B25), 26,400 lbf (LEAP-1B27) and 27,900 lbf (LEAP-1B28). Basic ratings for the MAX 9 are the LEAP- 1B27 and LEAP-1B28. According to IBA Insight, all MAX 8 200s and around 55% of MAX 8s are powered by LEAP-1B27 variants, and around 75% of MAX 9s are powered by LEAP-1B28 variants.

Aircraft certification pending, MAX 7 basic thrust ratings will also include the LEAP-1B25 and LEAP-1B27, and additionally 23,000 lbf (LEAP-1B21) and 24,000 lbf (LEAP-1B23) rated engines. MAX 10 basic ratings are identical to the MAX 9.

In-Service Performance

The CFM LEAP-1B was developed to achieve significant specific fuel consumption (SFC), nitrogen oxide (NOx) emission and noise emission benefits over CFM56-5B/-7B engines.

The engine was also developed to match CFM56-5B/-7B reliability and life cycle maintenance costs. Comparing typical reliability metrics such as inflight shutdowns, aborted take-offs, service interruptions and departure reliability, statistics are comparable and, for some metrics, consistently better. Airworthiness directives (ADs) since service entry stand at eight, less than both the CFM LEAP-1A and Pratt & Whitney PW1100G.

However, industry commentators would likely challenge whether life cycle maintenance costs will be matched, owing to time-onwing expectations and recent cost escalations. This principally relates to in-service and ongoing retrofits for which the previous engine bill of material continues to restrict timeon- wing. From some factions, there is a belief that during the engine development phase, there was greater emphasis placed on environmental engine benefits, notably, SFC, and that time-on-wing will not match CFM56-5B/-7B engines.

CFM International has promptly responded with retrofit development and fixes; increased maintenance, repair and overhaul (MRO) capacity; and spare engine coverage with increased production. Notable ongoing in-service retrofits for the LEAP-1B have been radial drive shaft bearing redesign following riveting issues; HPT shroud coating loss and resulting redesign; and a nonsynchronous vibration issue resulting in a new hard coating to the number three bearing spring finger housing. Upcoming retrofit work includes a reverse bleed system to mitigate against long-enduring fuel nozzle coking deposits, leading to premature shop visits and replacements.

Value and Market Commentary

IBA Insight identifies 3,750 LEAP-1B engines as being active, stored or parked on-wing of passenger delivered 737 MAX 200, MAX 8 and MAX 9 variants. Further, IBA estimates that around 430 LEAP-1B spare engines have been manufactured, representing around 10.3% of the total identifiable engine fleet of almost 4,200.
The LEAP-1B engine does not have the same utilization maturity in service as the LEAP-1A or PW1100G, due to the 737 MAX 8 entry into service date and a sustained period of grounding from March 2019 to December 2020. This has meant that retrofits impacting both LEAP-1A and LEAP-1B engines have typically occurred later for the LEAP-1B and will do with upcoming retrofits. A significant increase in spare engine deliveries in 2025 marks a change from previous years with performance restorations and further retrofits imminent.

Long-term lease rates in July 2025 for used and new engines range US$130,000 to US$150,000 per month, although there is divergent market sentiment on achievable lease rate factors. Short-term lease rates have been quoted at US$6,000-7,000 per day in 2025.

Presently, there is an equilibrium of supply and demand, reflected in the current market and Base Value relationship. Other than lease rates observed, used market transactions have been in small numbers. New engines transacting to engine lessors have been observed with discounts between 2%-4% (transactions for multiple LEAP-1Bs). For those acquiring spare engines, the Boeing-supplied Quick Engine Change (QEC) kit has caused delivery delays from late 2024 and into 2025.
Beyond 2025, it is expected that values will continue on an upward trajectory, a factor of OEM escalations on engine list prices; life-limited parts and maintenance costs; and the continued cycle of fleet replenishment from current generation A320ceo and 737NG to new technology A320neo and 737 MAX. Value opinion could alter should CFM International introduce a performance improvement package.