The engine family we know best.
The CFM56 is the most widely operated commercial jet engine ever built. It powers the aircraft that carry most of the world's short-haul traffic, and it is now moving through the most commercially interesting phase of its life — the one where the decisions get hard.
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Fleet figures published by CFM International. Thrust range 18,500–32,000 lb across the family, powering the Airbus A320ceo and Boeing Next-Generation 737 families.
Five variants. Five different commercial situations.
| Variant | Application | Thrust | Stages | Fleet position | What that means commercially |
|---|---|---|---|---|---|
| CFM56-3 | Boeing 737 Classic (-300/-400/-500) | 18,500–23,500 lb | 3 · 9 · 1 · 4 | Largely retired from passenger service; surviving airframes are freighter and cargo operations. | Value now sits almost entirely in used serviceable material and in supporting the remaining cargo fleet. Restoration cases are rare and need a hard commercial test. |
| CFM56-5A | Airbus A320ceo family (early) | 22,000–25,000 lb | 4 · 9 · 1 · 4 | Superseded on the line by the -5B; a shrinking installed base. | Thin support economics. Decisions here usually resolve to green time, exchange, or disassembly rather than to full restoration. |
| CFM56-5B | Airbus A320ceo family | 22,000–33,000 lb | 4 · 9 · 1 · 4 | One of the two backbone variants. Large active fleet, deep global shop and material support. | The most liquid CFM56 market alongside the -7B. Shop capacity, USM availability and lease alternatives are all real options, which makes the evaluation genuinely competitive. |
| CFM56-5C | Airbus A340-200/-300 | 31,200–34,000 lb | 4 · 9 · 1 · 5 | Four-engine widebody application; a small and specialised population. | Thin market, few shops, limited USM. Options narrow quickly, so planning has to start earlier than on the narrowbody variants. |
| CFM56-7B | Boeing 737 Next-Generation | 19,500–27,300 lb | 3 · 9 · 1 · 4 | The other backbone variant. Very large active fleet across passenger and freighter operations. | Deepest support and material availability of the family. Because alternatives are real, an unrepresented shop visit here is where the most value is quietly lost. |
Thrust ratings vary by specific model and installation. Treat this as orientation, not as a specification — on a live decision we work from the engine's own records.
The level of visit decides most of the bill.
On-wing
Work performed without removing the engine.
Cheapest by an order of magnitude and the least disruptive. The advisory question is whether an on-wing action genuinely resolves the driver or simply defers a removal into a worse slot.
Hospital visit
A limited removal to address a specific defect.
Fast and comparatively cheap, but it consumes a removal. If the engine is close to a performance restoration anyway, a hospital visit can be the most expensive cheap decision available.
Performance restoration
A workscope aimed at recovering exhaust gas temperature margin and time on wing.
The workhorse shop visit. Scope discipline is everything: the difference between a targeted restoration and a drifting one is usually seven figures, and it is decided in the findings review, not in the quote.
Full overhaul / piece-part
Complete disassembly to piece-part inspection.
The most thorough and the most expensive. Justified by life position and intended service life, not by a wish for completeness. Rarely the right answer for a late-life asset.
LLP replacement
Renewal of life-limited parts at their cycle limits.
Driven by certification limits, not by condition. Aligning LLP renewal with a shop visit avoids paying for the same removal twice — and mis-aligning them is one of the most common avoidable costs in the fleet.
The level of visit is a commercial decision wearing technical clothing. Choosing it before the findings are in is how budgets get set by the shop instead of by the owner.
Which paths belong on the table?
This tool deliberately produces no numbers. Anyone quoting a shop visit cost from three dropdowns is selling something. What it shows is the shape of the evaluation — which options belong on the table for a given situation, and the reasoning behind each. The actual answer comes from the records, the findings and the market on the day.
The market the retirements created.
As fleets retire, the CFM56 becomes as much a materials market as an engine market.
CFM reports more than a thousand CFM56 repair processes with commonality across the -5B and -7B, which broadens the pool of used serviceable material available to both. For an owner that cuts two ways: cheaper material to buy, and a real alternative to restoration when the asset is late in life.
- USMServiceable parts harvested from retired assets. Often the difference between a viable restoration and an uneconomic one.
- Green timeFlying the remaining life you already own instead of buying life you cannot recover. The dominant strategy late in an asset's life.
- Part-outDisassembly when the sum of the modules exceeds the assembled value. The decision is a valuation exercise, not a sentiment.
- Freighter demandCFM International reports 480 narrowbody freighters on CFM56 power, which continues to support demand well past passenger retirement.
Whichever variant you operate, the question is the same: what is this specific engine worth doing?
Send us the position and we will tell you how we would frame it.
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