Engine Overview
The CFM56-3B family supports Boeing 737 Classic operations, including -3B1 and -3B2 variants.
| Engine Family | CFM56-3 |
|---|---|
| Variant Focus | CFM56-3B1 / -3B2 |
| Takeoff Thrust | Approx. 18,500–22,000 lbf |
| Fan Diameter | Approx. 60 in |
| Applications | 737-300 / -400 / -500 |
| Market | Mature / legacy narrowbody |
Variants & Aircraft Applications
Commercial application and configuration vary by engine rating and aircraft model.
| Engine Variant | Primary Application |
|---|---|
| CFM56-3B1 | Boeing 737-300 and 737-500 |
| CFM56-3B2 | Boeing 737-300 and 737-400 |
Final applicability must be verified against current approved aircraft and engine documentation.
Global Fleet Footprint
CFM reports 256 operators for the overall CFM56-3 fleet as of April 2026, with nearly 230 million engine flight hours and more than 162 million cycles.
Fleet/operator counts evolve; use current OEM and operator records for transaction-level verification.
Representative CFM56-3B LLP P/Ns
| Module | P/N | Description |
|---|---|---|
| Fan/LPC | 335-009-306-0 | Booster Spool |
| Fan/LPC | 335-014-511-0 | Fan Disk |
| Fan/LPC | 335-006-414-0 | Fan Shaft |
| HPC | 1275M37P02 | HPC Front Shaft |
| HPC | 1589M66G02 | HPC Stage 1-2 Spool |
| HPT | 1475M29P03 | HPT Rotor Disk |
| LPT | 301-331-125-0 | LPT Stage 1 Disk |
Reference only. LLP applicability and certified life are configuration/revision specific and must be verified against current approved records.
Maintenance & Shop-Visit Planning
| Performance | EGT margin and hot-section condition remain central to on-wing planning. |
|---|---|
| Environment | High-OAT and harsh operating conditions can shorten removal intervals. |
| LLP planning | Fan, core and LPT LLP groups have different life limits and replacement economics. |
| Workscope | Core restoration, module overhaul and green-time replacement are often compared commercially. |
There is no single universal overhaul interval applicable to every engine in this family.
Indicative Shop-Visit Cost Context
Historical public references place many CFM56-3 core/restoration visits around the low seven figures, while heavier overhaul plus LLP replacement can materially exceed that. For current 2026 decisions, engine replacement value versus shop-visit cost should be compared case by case.
| Main drivers | Workscope, LLP status, hot-section material, repairability, USM availability, labor, shop capacity and engine configuration. |
|---|---|
| Commercial check | Compare planned shop-visit investment with current engine and green-time replacement value. |
Budgetary context only; not a CFM Gate quotation.
Commonly Sourced CFM56-3B Material
Typical CFM56-3B sourcing demand includes HPT blades/nozzles, fan and booster material, HPC hardware, LPT disks and shafts, fuel and oil accessories, valves, pumps, starters and green-time engine assets.
CFM Gate's RFQ/OFFER database is not yet reliably tagged by engine family, so this page does not publish an artificial “top P/N” ranking.
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