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Engines · CFM International

CFM56

CFM56-5A, CFM56-5B, CFM56-7B

out of production, large in service fleet 3 min read · updated 11 October 2026 · checked 11 October 2026

Turbofan model under test
An ultra high bypass ratio turbofan model in a NASA wind tunnel. Credit NASA.

At a glance

Engine card

VariantsCFM56-5A, CFM56-5B, CFM56-7B
ArchitectureTwo shaft turbofan, bypass ratio around 5.5:1
Thrust18,500 to 34,000 lbf
ApplicationsA320ceo family, 737 NG
Built byCFM International
StatusOut of production, very large in service fleet

Program and production

New CFM56 production for commercial airframes has ended, and the programme is entirely an aftermarket story now. That does not make it small. With the 737 NG and A320ceo fleets both being flown well past their planned retirement dates, the CFM56 is doing more work than anyone forecast five years ago.

The clearest signal is CFM's own behaviour. The company has boosted high pressure turbine blade output and repair capability specifically to meet extended demand for CFM56 engines. An original equipment manufacturer does not expand capacity on an out of production engine unless the forecast flying hours justify it.

The reason is upstream. LEAP and GTF deliveries have not arrived fast enough to retire the previous generation on schedule, and the GTF powder metal inspection campaign has grounded a large part of the A320neo fleet that was delivered. Operators short of capacity keep the older aircraft flying, and that lands on the CFM56.

Technical and maintenance

This is a mature engine with no systemic defect. The problem is access to capacity and parts.

Industry analysis of engine stand utilisation in 2026 puts the CFM56-7B, CFM56-5A and 5B, and the V2500 at the centre of shop visit demand, driven by ageing fleets and the complexity of the work required. Engine stands are a genuine physical bottleneck, not an abstract one.

In plain terms

An engine stand is the cradle that holds an engine during transport and overhaul. There are a finite number of them for each engine type, and a shop cannot start work without one. When stands are scarce, a serviceable engine can sit waiting for a frame to be mounted on.

On the line

Book shop slots earlier than historical planning assumptions suggest, and treat quoted turn times as optimistic. The same MRO capacity supporting your CFM56 overhauls is also absorbing the GTF inspection campaign, so the competition for slots is not easing quickly. Where a removal can be planned rather than forced, plan it, because an unplanned removal now queues behind a much longer line than it did three years ago. Used serviceable material availability has tightened as retirements slowed, which affects both cost and lead time on rotables.

Applications and fleet

The CFM56-7B is the sole engine on the 737 NG, so that entire fleet depends on it. The CFM56-5A and 5B compete with the V2500 on the A320ceo family.

The decline in share has been slow. CFM56 powered flights fell from roughly 43 percent of A320 and 737 family activity in 2024 to around 42 percent in 2026, and V2500 from 23 to 22 percent. For comparison, in February 2019 the CFM56 powered more than 55 percent of A320 family activity. The long arc is downward, but the recent slope is close to flat, and that flatness is the story.

Safety

No significant developments since 11 October 2026.

No Airworthiness Directive of fleet wide significance was issued against the family in this period.

Sources