CFM International LEAP-1B
831 US-registered aircraft fly this program — 1,662 installed engines across 4 registry codes
Program snapshot(US registry)
4 registry engine codes aggregated
No meaningful US teardown supply yet — 831 aircraft flying, median build year ≈2023; the retirement curve is the thing to watch.
FAA registry data, US-registered aircraft only. Deregs = domestic deregistrations — a teardown proxy that also captures re-registrations and some unflagged exports, never a confirmed part-out count. Median build year is a tails-weighted median of per-variant medians (≈). 694 of 831 active tails are registered under generic series codes rather than a specific variant, so per-variant splits are partial.
Registry codes under this program
FAA registry — as registered, variants + generic series rows
| Engine model | Active tails | Engine units | Median build yr | Deregs since ’23 | Exported | Avg age at dereg |
|---|---|---|---|---|---|---|
| LEAP-1B28 seriesgeneric code | 650 | 1,300 | 2023 | 0 | 4 | 4.2 yr |
| LEAP-1B25 | 101 | 202 | 2023 | 0 | 0 | — |
| LEAP-1B27 seriesgeneric code | 44 | 88 | 2021 | 0 | 6 | 2 yr |
| LEAP-1B28B | 36 | 72 | 2022 | 0 | 2 | 3.5 yr |
Counts reflect the engine model exactly as registered. Registry-wide, roughly 57% of engine records name a specific variant; the rest carry generic series codes, so generic rows coexist with variant rows and per-variant figures are partial. Deregs = domestic deregistrations (a teardown proxy, not confirmed part-outs); exported aircraft left the US fleet intact.
Airframe applications
FAA registry + BTS T-100 family rollups
| Family | Tails on this program | Family US fleet | Avg fleet age | Built 15+ yrs ago | Avg cycles / yr |
|---|---|---|---|---|---|
| 737 | 831 | 2,751 | 13.7 yr | 1,093 | 1,182 |
“Tails on this program” counts US-registered aircraft the registry rollup maps to both the family and a LEAP-1B engine code — an undercount, since not every tail resolves to a family. Family fleet, age, and cycles columns describe the WHOLE family across every engine option, not just LEAP-1B-powered aircraft (cycles from BTS T-100, 2025).
Airworthiness Directive activity
FAA / EASA public regulatory data
- FAA AD 2025-14-08effective Aug 25, 2025Prohibition
The FAA is superseding Airworthiness Directive (AD) 2023-23-12 for all CFM International, S.A. (CFM) Model LEAP-1B21, LEAP-1B23, LEAP- 1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 engines. AD 2023-23-12 required replacing certain high-pressure turbine (HPT) rotor stage 1 disks and a certain compressor rotor stages 6-10 spool. Since the FAA issued AD 2023-23-12, the manufacturer has identified additional parts that were manufactured from material suspected to have reduced material properties due to iron inclusion, which prompted this AD. This AD retains the requirements to replace certain HPT rotor stage 1 disks and a certain compressor rotor stages 6-10 spool. This AD also expands the applicability to include additional affected HPT rotor stage 1 disks that were manufactured from the same material suspected to have reduced material properties due to iron inclusion. The FAA is issuing this AD to address the unsafe condition on these products.
- FAA AD 2025-04-12effective Apr 8, 2025Prohibition
The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1A, LEAP-1B, and LEAP- 1C engines. This AD was prompted by a manufacturer investigation that revealed a quality escape for low-pressure turbine (LPT) disks made from forgings with nonconforming grain size. This AD requires removal and replacement of the LPT stage 4 and stage 5 disks. The FAA is issuing this AD to address the unsafe condition on these products.
- FAA AD 2024-25-02effective Feb 12, 2025Mixed actions
The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1B engines. This AD was prompted by a report of a quality escape involving certain high- pressure compressor (HPC) stage 2 seals manufactured without detailed finish machining, which could result in deeper rubs and mechanical damage to the seal teeth of the stage 3-4 compressor rotor blisk (stage 3-4 blisk) of the mating compressor rotor during initial operation. This AD requires a visual inspection of the HPC stage 2 seal, a visual inspection of the forward arm seal teeth of the stage 3-4 blisk, an eddy current inspection (ECI) of the forward arm seal teeth of the stage 3-4 blisk, and replacement of the HPC stage 2 seal and the stage 3-4 blisk, if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
- FAA AD 2023-23-12effective Jan 16, 2024Prohibition
The FAA is adopting a new airworthiness directive (AD) for all CFM International, S.A. (CFM) Model LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP- 1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 (LEAP-1B) engines. This AD was prompted by a manufacturer investigation that revealed that certain high-pressure turbine (HPT) rotor stage 1 disks (HPT stage 1 disks) and a certain compressor rotor stages 6-10 spool were manufactured from material suspected to have reduced material properties due to iron inclusion. This AD requires replacing certain HPT stage 1 disks and a certain compressor rotor stages 6-10 spool. The FAA is issuing this AD to address the unsafe condition on these products.
- FAA AD 2023-15-05effective Aug 25, 2023Prohibition
The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737 airplanes equipped with CFM International, S.A. (CFM) Model LEAP-1B series turbofan engines. This AD was prompted by a report indicating that use of engine anti-ice (EAI) in dry air for more than five minutes during certain environmental and operational conditions can cause overheating of the engine inlet inner barrel beyond the material design limit, resulting in failure of the engine inlet inner barrel and severe engine inlet cowl damage. This AD requires revising the existing airplane flight manual (AFM) to limit the use of EAI in certain conditions and revising the operator's existing minimum equipment list to prohibit dispatch under a certain item. The FAA is issuing this AD to address the unsafe condition on these products.
Directives in the FAA / EASA corpus we have processed whose text names LEAP-1B engine models — not a complete historical AD list, and text matching can include airframe directives that reference the engine. An AD is a compliance requirement that drives scheduled work on a regulator's clock — a regulatory compliance signal, not a failure prediction, and no comment on this engine's reliability.