CFM International LEAP

Design

The LEAP uses 15% less fuel and produces 15% less CO₂ compared to the CFM56. It uses a scaled-down version of the low-pressure turbine used on the General Electric GEnx engine. The fan blades are made of composite materials using a resin transfer molding process and untwist under aerodynamic and centrifugal loads to maintain aerodynamic efficiency.

Although designed with a higher overall pressure ratio than the CFM56, the engine operating limit is lower to improve durability and service life. It uses a higher proportion of composite materials, features the second-generation Twin Annular Pre-mixing Swirler (TAPS II) combustor, and has a bypass ratio of approximately 10:1 to 11:1. The high-pressure compressor has a pressure ratio of 22:1, approximately double that of the CFM56. The turbine shrouds, made from ceramic matrix composites (CMCs), are lighter than those on the CFM56.

The LEAP incorporates an eductor-based oil cooling system, derived from the GEnx design. This system includes oil coolers mounted on the fan duct and uses a venturi effect to maintain oil pressure within the internal sump. Additionally, the LEAP includes some of the first FAA-certified 3D-printed components used in a commercial jet engine.

The LEAP-1C variant, developed for the Chinese-built Comac C919, reportedly omits some of the advanced technologies found in other LEAP models. According to industry sources, this decision was influenced by concerns that the technology could be stolen and put into the CJ-1000A engine being developed by another state-owned manufacturer, the Aero Engine Corporation of China. Some analysts have described the LEAP-1C as more closely related in capability to an upgraded CFM56 than to other LEAP variants.

Development

The LEAP incorporates technologies that CFM developed as part of the LEAP56 technology acquisition program, which CFM launched in 2005. The engine was launched as LEAP-X on 13 July 2008, intended as a successor to the CFM56.

In 2009, COMAC selected the LEAP engine for the C919. 28 development engines were used by CFM to achieve engine certification, and 32 more used by Airbus, Boeing and COMAC for aircraft certification and other test programs.

CFM carried out the first test flight of a LEAP-1C in Victorville, California, with the engine mounted on the company Boeing 747 flying testbed aircraft on 6 October 2014. The -1C version has a thrust reverser with a one-piece O-Duct replacing the more usual two-piece D-Duct. There are no drag links for the blocker doors giving a smoother flowpath for the fan air.

It obtained its 180-minute ETOPS approval from the U.S. Federal Aviation Administration and the European Aviation Safety Agency on 19 June 2017.

Orders

On 20 July 2011, American Airlines announced that it planned to purchase 100 Boeing 737 aircraft featuring the LEAP-1B engine. The project was approved by Boeing on 30 August 2011, as the Boeing 737 MAX. Southwest Airlines was the launch customer of the 737 MAX with a firm order of 150 aircraft.

The list price was for a LEAP-1A, and for a LEAP-1B.

CFM International were offering rate-per-flight-hour support agreements (also known as "power by the hour" agreements) for the engine. For a LEAP-1A engine, costs were around per engine, per day, compared to per engine, per day for the prior-generation CFM56.

In 2016, CFM booked 1,801 orders, and the LEAP backlog stood at more than 12,200, worth more than at list price.

By July 2018, the LEAP had an eight-year backlog with 16,300 sales. At that time, more LEAPs were produced in the five years it was on sale than CFM56s in 25 years. It is the second-most ordered jet engine behind the 44-year-old CFM56,

In 2020, GE Aviation reported that CFM had lost 1,900 orders for LEAP engines worth ( each), reducing the backlog value to . More than 1,000 cancellations came from Boeing 737 MAX orders being canceled among the Boeing 737 MAX groundings, while the remainder came from the impact of the COVID-19 pandemic on aviation.

In May 2025, the United States Department of Commerce paused the export of LEAP engines to COMAC. The restrictions were lifted in July 2025 amid de-escalating U.S.-China trade tensions, with the U.S. permitting GE Aerospace to restart shipments.

Production

In 2016, the engine was introduced in August on the Airbus A320neo with Pegasus Airlines and CFM delivered 77 LEAP. This is compared to the 1,700 CFM56 produced in 2016.

To cope with the demand, CFM duplicated supply sources on 80% of parts and subdivided assembly sites, already shared between GE and Safran. Safran assembles LEAP engines in Villaroche, France, and Safran and GE each assemble half of the annual volume.

In 2018, 1,118 engines were delivered.

Over the first half of 2019, CFM revenues were up by 23% to with 1,119 engine deliveries; declining sales of CFM56 (258 sold), more than offset by LEAP (861 sold).

In 2019, LEAP production rose to 1,736 engines, and orders and commitments reached 1,968 amid the 737 MAX groundings, compared with 3,211 for 2018, for a stable backlog of 15,614 (compared to 15,620). By March 2022, CFM intended to output 2,000 engines in 2023, up from 845 deliveries in 2021. In 2023, CFM booked over 2,500 orders, resulting in a backlog of 10,675, delivered 1,570 Leap engines, up by 38% from 1,136 in 2022, and was expecting 20-25% more deliveries for 2024.

The troubled introduction of the Pratt & Whitney PW1100G on the A320neo motivated customers to choose LEAP engines. LEAP market share rose from 55% to 60% in 2016, but orders for 1,523 aircraft (%) had not specified which engine would be chosen. As an example of PW1100G reliability issues, 9% of LEAP-powered A320neos were out of service for at least one week in July 2017, compared with 46% of those using the PW1100G.

A contract for the production of components for the low-pressure turbine of the LEAP engine was signed on February 12, 2025, between Safran Aircraft Engines and India's Titan Engineering and Automation Limited. Manufacturing will start from 2026. An additional agreement was signed for manufacturing turbine forged parts with Hindustan Aeronautics Limited.

Operations

The Boeing 737 MAX LEAP-1B started revenue service in May 2017 with Malindo Air with 8 hours of daily operation, while the A320neo LEAP-1A surpassed 10 hours per day by July.

In October 2017, an exhaust gas temperature shift was noticed during a flight and a CMC shroud coating in the high-pressure turbine was seen flaking off in a borescope inspection. This caused more hot gas leakage past the turbine than normal. A design change was required to the coating.

Applications

File:Airbus A321-251NX (TC-RDK), Istanbul SAW (TR) -- 2024 -- 0139.jpg|The LEAP-1A is one of two engine options on the Airbus A320neo family. File:Boeing 737-9 MAX CFM LEAP-1B PAS.jpg|The LEAP-1B is the exclusive engine option for the Boeing 737 MAX. File:LEAP-1C (tight crop).png|The LEAP-1C is currently the exclusive engine option for the Comac C919.

Specifications

Notes

References

References

1. (6 September 2013). "CFM launches a new era as first LEAP engine begins ground testing". [[CFM International]].
2. https://www.cfmaeroengines.com/leap
3. Chandler, Jerome Greer. (18 May 2017). "Taking the LEAP: CFM's successor to the fabulous 56". Aviation Pros.
4. Guy Norris. (13 April 2015). "Pratt Targets Hot, Rotating Blade Use Of CMCs".
5. (6 October 2009). "New engines: flurry of activity despite downturn". Flightglobal.
6. Guy Norris. (28 October 2013). "Smooth Start To Fast-Paced Leap-1A Test Program".
7. Tomas Kellner. (14 April 2015). "The FAA Cleared the First 3D Printed Part to Fly in a Commercial Jet Engine from GE". GE.
8. Bogaisky, Jeremy. (2022-09-20). "China Preps To Launch Its First Big Passenger Jet. It's No Threat To Boeing Or Airbus—Yet".
9. "LEAP Turbofan Engine, History".
10. (13 June 2005). "CFM Laying the Technology Foundation for the Future".
11. (13 July 2008). "CFM Unveils New LEAP-X Engine". [[CFM International]].
12. (21 December 2009). "CFM International to provide engines for COMAC's C919". flightglobal.
13. david kaminski morrow. (22 April 2015). "First Leap-powered A320neo moved to flight-test team". flightglobal.
14. Guy Norris. (20 November 2015). "CFM Lifts Veil On Leap Engine Test Details". Aviation Week & Space Technology.
15. Guy Norris. (13 October 2014). "CFM Marks 40th Anniversary With Leap-1 Flight Test".
16. (21 June 2017). "LEAP engines awarded 180-minute ETOPS certification". CFM International.
17. (20 July 2011). "Boeing and American Airlines Agree on Order for up to 300 Airplanes – Jul 20, 2011". Boeing.mediaroom.com.
18. [https://www.forbes.com/sites/afontevecchia/2011/08/30/boeing-confirms-duopoly-with-airbus-by-announcing-re-engining-of-737/ Boeing Confirms Duopoly With Airbus Announcing Re-Engining Of 737] {{Webarchive. link. (5 March 2016 . Forbes)
19. [http://www.flightglobal.com/blogs/flightblogger/2011/08/boeing_rendering_illustrates_m/ Boeing rendering illustrates major changes to 737NE] {{Webarchive. link. (16 October 2014 . flightglobal.com)
20. (13 December 2011). "Southwest Airlines Will Become Launch Customer for the New Boeing 737 Max Aircraft – Southwest Airlines Newsroom". Swamedia.com.
21. Alan Dron. (30 March 2018). "Lion Group completes $5.5 billion LEAP-1A purchase". Aviation Week Network.
22. (8 August 2017). "ALC finalizes $348 million CFM LEAP-1B engine order". CFM.
23. (15 June 2015). "Zhejiang Loong Air signs RPFH agreement for CFM56-5B engines". Aviation News Ltd.
24. (14 February 2017). "2016 CFM orders surpass 2,600 engines". CFM International.
25. Chris Kjelgaard. (4 July 2018). "CFM Confident Leap Production Can Catch Up Soon". AIN online.
26. Stephen Trimble. (15 July 2018). "CFM looks to another Leap forward at Farnborough". Flightglobal.
27. (22 March 2018). "GE/CFM in "lockstep" with Boeing on NMA". Leeham News.
28. Jon Hemmerdinger. (27 April 2021). "GE Aviation lost 1,900 Leap orders in 12 months". Flightglobal.
29. "U.S. Blocks Sale of CFM Aircraft Engine to China". Flying Magazine.
30. (2025-07-03). "US lets GE restart jet engine shipments to China's COMAC, source says". Reuters.
31. Stephen Trimble. (19 June 2017). "GE ups production target to meet Boeing and Airbus demand". Flight Global.
32. Max Kingsley-Jones. (15 November 2016). "CFM quietly confident on Leap production ramp-up". Flight Global.
33. (16 November 2016). "New GE plant highlights CFM ramp-up strategy on Leap". Flight Global.
34. (15 December 2016). "CFM confirms initial LEAP-1A and LEAP-1B assembly allocation". MRO Network.
35. Jon Hemmerdinger. (1 February 2019). "MID SUPPLY CHAIN RECOVERY CFM's Leap deliveries doubled in 2018 amid supply chain recovery". Flightglobal.
36. David Kaminski-Morrow. (5 September 2019). "Leap production edges towards positive contribution". Flightglobal.
37. David Kaminski-Morrow. (27 February 2020). "CFM to build 10 737 Max engines weekly for 2020". Flightglobal.
38. Jon Hemmerdinger. (11 March 2022). "GE Aviation confident in ability to double Leap output by 2023". FlightGlobal.
39. Dominic Perry. (18 February 2024). "Leap sales 'not threatened' by GTF Advantage performance gain, says Safran chief". FlightGlobal.
40. Rick Clough. (22 August 2017). "Pratt's $10 Billion Jet Engine Lags GE by 10-to-1 on New Orders". Bloomberg.
41. (2025-02-13). "Safran selects TEAL for the production of LEAP engine turbine parts in India". The Economic Times.
42. (2025-02-13). "Aero India 2025{{!}} HAL signs agreement with Safran Aircraft Engines and Collins Aerospace". The Hindu.
43. Stephen Trimble. (30 October 2017). "CFM reviews fleet after finding Leap-1A durability issue". Flightglobal.
44. Sean Broderick. (31 October 2017). "Safran Reveals Leap Turbine Shroud Coating Issue Issue". Aviation Week Network.
45. Rick Clough and Julie Johnsson. (5 March 2018). "Fix for New Boeing, Airbus Planes".
46. Chris Kjelgaard. (17 July 2018). "CFM Fixes Leap Turbine Shroud Coatings". AIN online.
47. "The Leap Engine". CFM International.
48. (2 August 2016). "Pegasus starts flying Leap-1A-powered A320neo". Flight Global.
49. (22 May 2017). "Malindo operates world's first 737 Max flight". Flight Global.
50. Alfred Chua. (28 May 2023). "'A new beginning': Comac C919 enters commercial service".
51. (30 May 2018). "Type Certificate data sheet for LEAP-1A & LEAP-1C Series Engines". [[EASA]].
52. (16 June 2017). "Type Certificate data sheet for LEAP-1B Series Engines". [[EASA]].
53. (9 November 2011). "Comparing the new technology Narrow-body engines: GTF vs LEAP maintenance costs". Airinsight.
54. (June 2017). "LEAP overview". CFM International.
55. Vladimir Karnozov. (19 August 2019). "Aviadvigatel Mulls Higher-thrust PD-14s To Replace PS-90A". AIN Online.
56. "PD-14: New generation engine for MC-21".
57. (June 2015). "LEAP-1C: integrated propulsion system for the Comac C919". Safran Aircraft Engines.
58. (2017-03-02). "EASA.A.064 - Airbus A318, A319, A320, A321 Single Aisle {{!}} EASA".