The Part That Stops the Engine

In the CFM56 supply chain, the most expensive component is often not the one with the highest price. It is the one nobody can deliver.

Every commercial aircraft tells two stories. Passengers see the departure board. Maintenance organizations see the material list. Between those two sits one of the most consequential problems in commercial aviation today.

An engine can arrive at an MRO facility, complete disassembly and inspection, and receive a fully developed workscope. Then everything stops. Not because the repair is technically difficult. Not because the shop lacks capacity. Because one critical component cannot be sourced with confidence.

In today’s CFM56 supply chain, a single unavailable part can hold an entire engine for weeks or months.

The consequences run well past the maintenance schedule. Aircraft stay grounded longer than planned. Operators extend leased engines or secure replacements at elevated rates. Fleet schedules become harder to protect. Cash exposure rises, and capital stays tied to an asset that cannot generate revenue.

The missing component becomes the most expensive one in the engine. Not because of what it costs, but because of everything it prevents.

Inside the CFM56 supply chain

The CFM56 is one of the most successful commercial engines ever built. CFM International reports more than 23,000 still in service with over 600 operators, supported by an open network of more than 40 licensed MRO shops. In January, CFM and IATA renewed their aftermarket agreement through 2033, with CFM accounting for roughly a third of CFM56 overhauls. The rest of that work is competitive.

That scale is part of the problem.

Thousands of Boeing 737NG and Airbus A320ceo aircraft keep flying because delayed deliveries and production constraints have held older fleets in service far longer than airlines planned. IATA now puts delivery shortfalls at more than 5,300 aircraft and the order backlog above 17,000, roughly twelve years of current production capacity. Average fleet age has climbed to 15.1 years.

Every one of those numbers lands in the aftermarket. More demand for engine maintenance. Heavier competition for repair capacity. Tighter availability of used serviceable material. Longer and less predictable lead times on critical components.

IATA and Oliver Wyman estimated the cost of supply chain constraints to airlines at more than $11 billion in 2025. That included $3.1 billion in additional maintenance costs and $2.6 billion in excess engine leasing, driven largely by engines sitting on the ground longer than planned.

One figure explains the pressure better than the rest of them combined. Two full-life engines now represent close to 80 percent of the value of a new aircraft. Two decades ago that share was 20 to 30 percent. Within six years of purchase, a pair of engines is worth more off the wing than on it.

Competition is no longer limited to securing a shop slot. It now covers repair capacity, replacement material, OEM availability, engine access, and the ability to predict when a component will actually arrive.

Material strategy starts before the engine does

For years, planning a shop visit mostly meant booking a slot. That is now the smaller half of the job.

The operators who protect their turnaround times assess material exposure before the engine comes off the wing. Historical findings. Life-limited parts. Fleet trends. Anticipated module exposure. Repair alternatives. Exchange opportunities. Used serviceable material. Each of these can move turnaround time as much as the technical repair.

Once the engine is in the shop and findings begin to accumulate, time stops working in your favor. Decisions get more expensive. Alternatives narrow. Pressure starts shaping the workscope instead of judgment.

The answer is not always buying more material. Sometimes it means evaluating repair against replacement earlier. Sometimes it means securing serviceable material before induction. Sometimes it means adjusting the workscope without compromising airworthiness or reliability. And sometimes it means protecting the engine’s remaining economic value rather than pursuing the most extensive repair available.

Visibility is a competitive advantage

Long lead times are difficult. Unknown lead times are worse.

Operators can build maintenance and fleet plans around realistic expectations. What they cannot manage is uncertainty. Knowing whether a component arrives in six weeks or six months determines whether an aircraft stays available, whether a lease has to be extended, and whether a different maintenance strategy becomes necessary.

In this market, visibility is worth as much as inventory. A credible lead time lets an operator plan. An unreliable one pushes risk across maintenance, finance, leasing, scheduling, and commercial operations, usually without anyone naming it as risk.

Where Miami sits in this

South Florida holds an unusual concentration of this business. Engine shops, component repair, traders, lessors, and the parts inventory that moves between them. When material availability decides turnaround time, proximity to inventory becomes a commercial advantage rather than a logistics detail. That is part of why the region’s aftermarket economy has held its position while the fleet it serves has aged.

The larger point

Supply chains rarely make headlines. Passengers will never know why an aircraft returned to service two months late. Behind every delayed engine is a sequence of operational and commercial decisions that started long before the first wrench touched the hardware.

Today’s CFM56 supply chain rewards organizations that treat material planning as part of maintenance strategy rather than as procurement.

The objective was never simply to repair the engine. It is to return the aircraft to revenue service on schedule, with a workscope that makes technical and commercial sense.

Sometimes the part that costs the least on paper becomes the most expensive decision in the entire shop visit.