Insight for ACMI and Charter Capacity

What Is ACMI Wet Leasing? Complete Guide for Airlines

01/12/2025

ACMI sits in a weird but very powerful corner of aviation. You are not buying an aircraft, you are buying flying hours on somebody else's metal, with their crews and their technical operation. For many airlines that difference is the line between being able to serve demand this season or leaving cash on the table. This guide draws on real-world experience from industry professionals such as Joseph Amissah of Blue Cube Aviation, who has nearly three decades working in ACMI and aircraft leasing.

This guide walks through what ACMI actually is, how contracts work, who uses it, and the traps that airlines and operators keep falling into.

1. What ACMI Really Means

ACMI stands for Aircraft, Crew, Maintenance, Insurance.
The provider supplies:

  • The aircraft, on its own AOC

  • Flight deck and cabin crew

  • Line and base maintenance

  • Hull and third-party liability insurance

The client airline is still on the hook for fuel, overflight and airport charges, ground handling, catering, station costs, marketing and ticketing, schedule planning, and revenue management. In other words, the ACMI airline runs the flying; you run the commercial side.

Most ACMI contracts are priced per block hour with a monthly minimum. You pay for guaranteed availability, not just the hours you actually end up flying.

2. ACMI vs Dry Lease vs Charter

A lot of people throw "wet lease" and "leasing" around like they mean the same thing. They don't.

  • In a dry lease, you get the airframe and sometimes engines. You put it on your AOC, with your crews, maintenance program and manuals. This is a long-term fleet and balance sheet decision.

  • In a pure charter, a client hires an aircraft for a specific mission: a tour series, sports team, government flight, ad-hoc contract. That client is not usually an airline that then sells onward seats to the public on its own code.

  • In an ACMI wet lease, a carrier buys capacity to fly its own scheduled network or charter programs, but with another airline actually operating the aircraft.

So ACMI sits between long-term fleet finance and short-term charter. It is a flexible capacity tool rather than a permanent fleet addition.

3. Where ACMI Fits In An Airline Strategy

You rarely see a carrier building its entire business on ACMI, although there are exceptions. For most airlines, ACMI is used to:

  • Cover seasonal peaks where buying or long-term leasing extra aircraft would make no sense

  • Bridge delays in new aircraft deliveries or heavy checks

  • Cover AOG situations or unexpected technical downtime

  • Test new routes or bases before committing to own metal

  • Launch a startup carrier while its own AOC and fleet plan are still in progress

If an airline is using ACMI year-round on core routes, something deeper is going on: capital constraints, credit issues, fleet transition, or management betting on extreme flexibility over ownership.

4. How ACMI Contracts Are Structured

A typical ACMI agreement will cover at least the following points:

  • Term: anything from ad-hoc cover on a single route to a full season or multi-year deal

  • Aircraft type and configuration: model, seat count, cabin layout, optional equipment

  • Monthly minimum: guaranteed block hours, often with a band where a different hourly rate applies above or below the target

  • Positioning and return flights: who pays, how they are priced

  • Crew costs: what is included, what attracts extra charges (night stops, special basing, per diems)

  • Maintenance support away from base: spares, engineers, hangar access at outstations

  • Performance metrics: on-time performance, dispatch reliability, handling of disruptions

  • Commercial restrictions: where the aircraft can operate, codeshare rules, branding, livery, PR handling

Good contracts deal very clearly with disruption scenarios: who pays when ATC strikes, weather hits, or airports melt down. Poor contracts leave all of that to "good faith" and then everyone fights once the season turns ugly.

5. Pricing: What Really Drives The Hourly Rate

Rates move around a lot with market cycles, fuel, crew availability and demand for specific aircraft types. Instead of chasing a "typical" figure, focus on the drivers:

  • Aircraft type and age: new-gen narrowbodies and widebodies command a premium

  • Season and region: European summer, Hajj, and holiday peaks often push prices higher

  • Basing and positioning: remote bases and complex rotations add cost

  • Monthly volume: bigger hour commitments usually bring down the rate per hour

  • Risk profile of the client: weak balance sheets or payment history mean higher pricing or tighter terms

Most deals have extra charges for de-icing, unusual airports, additional insurance cover, special training, or security requirements. Ignore those and your budget will be wrong by a painful margin.

6. Benefits For Airlines

The main advantages of ACMI for airlines are blunt:

  • Speed: you can add capacity in weeks rather than waiting months or years for deliveries or dry lease slots

  • Capital light: no need to purchase aircraft or sign long multi-year leases

  • Operational backup: you can keep selling tickets while your own fleet is in heavy checks or stuck with OEM issues

  • Regulatory shortcut for startups: a new airline can start flying on someone else's AOC while working on its own approvals

The flip side: ACMI is usually more expensive per hour than operating your own aircraft once you are scaled, capitalised and fully staffed. It is a tool, not a free lunch.

7. Risks And Drawbacks For Airlines

ACMI has real downside when handled badly:

  • Dependency on the provider: if they underperform, you take the reputational and commercial hit

  • Limited control: you do not control the crews or maintenance culture, yet your brand is on the ticket

  • Contract opacity: vague service levels and unclear disruption rules invite conflict

  • Financial risk: prepayments and minimum hour commitments can become a problem if your demand forecast was too optimistic

The biggest mistake airlines make is treating ACMI as a simple "aircraft rent" instead of a complex operational partnership that can make or break a season.

8. Economics And Pressure Points For ACMI Operators

On the operator side, ACMI can look attractive from afar and brutal up close.

Operators take on:

  • Fleet ownership or long-term leases

  • Crew recruitment and training at scale

  • Heavy exposure to schedule changes and irregular operations

  • Credit risk on airlines that may not pay on time

Margins can be thin once you strip out positioning flights, crew costs, maintenance surprises and unpaid hours due to client-driven schedule changes. A carrier that looks cheap on paper might be cutting corners somewhere in order to survive.

When an airline selects an ACMI partner, the real question is not "who is cheapest?" but "who will still be alive and operating properly when the peak hits?"

9. How ACMI Deals Are Actually Done

In practice, a lot of ACMI deals still run on relationships and phone calls. The basic process usually looks like this:

  1. Requirement definition: the airline sets aircraft type, base, season, hour profile, and any special needs.

  2. Request to market: either direct to operators or via brokers who know which carriers genuinely have capacity.

  3. Indicative offers: rate per block hour, aircraft tail options, constraints, and early contract comments.

  4. Term sheet and KYC: commercial points narrowed, legal and compliance checks on both sides.

  5. Full contract: service levels, payment schedule, penalties and carve-outs agreed.

  6. Operational setup: crew hotels, station procedures, manuals, IT links, branding, and PR playbook.

The more precise the initial requirement, the better the end result. "We need a narrowbody somewhere in Europe next summer" is not a brief; it is a recipe for confusion and weak pricing.

10. What Airlines Should Prepare Before They Shop For ACMI

If you want serious quotes and not just ballpark numbers, show up prepared. At minimum, have:

  • Clear schedule and base plan

  • Estimated monthly block hours and seasonality

  • Airport list with curfews and restrictions

  • Slot status and any special operational constraints

  • Preferred aircraft types and acceptable alternatives

  • Credit information and payment terms you can realistically meet

The more serious you look on paper, the more credible operators will prioritise you when demand for aircraft is tight.

11. Common Mistakes And Painful Lessons

People who work ACMI every season keep seeing the same errors:

  • Airlines chasing the absolute lowest rate and ignoring operator strength

  • Contracts with unclear clauses around disruption, penalties, and minimum hours

  • Underestimating how crew fatigue rules and union agreements affect availability

  • Ignoring passenger experience: odd cabin layouts, old cabins, or strange liveries with zero communication

  • Leaving ACMI planning too late, then taking whatever is left at a premium

Fixing these issues usually costs more than doing it right at the start.

12. When ACMI Makes Sense – And When It Doesn't

ACMI is a powerful tool when an airline:

  • Has a clear, time-bound spike in demand

  • Faces temporary fleet or certification constraints

  • Wants to test new routes or markets fast

  • Needs backup capacity while restructuring its own fleet

It makes far less sense when management sees it as a lazy substitute for proper fleet planning, or when ACMI is used year after year to compensate for deeper structural problems. At that point, you are just paying extra to avoid hard decisions.

ACMI Wet Lease FAQ

1. What does ACMI actually stand for?
ACMI stands for Aircraft, Crew, Maintenance, and Insurance. The provider supplies all four; the client airline covers fuel, airport fees, catering, and commercial risk.

2. How is ACMI different from a dry lease?
In a dry lease you get only the aircraft and maybe engines. You operate it on your own AOC, with your own crew and ops. In ACMI, the provider flies on their AOC with their crew and manages technical ops.

3. Who typically uses ACMI capacity?
Airlines with seasonal peaks, new routes, AOG problems, certification delays, or financial constraints. Startups also use ACMI when they do not yet have an AOC or their own fleet.

4. How are ACMI contracts usually priced?
Most deals are priced per block hour with a minimum guaranteed number of hours per month. Extra charges can include positioning flights, de-icing, and special crew costs.

5. What is a typical ACMI contract length?
Anything from one-off ad-hoc coverage to 3–12 months for seasonal programs. Multi-year ACMI contracts exist but are less common and usually very specific to an airline's strategy.

6. Who holds the operational and safety responsibility?
The ACMI provider, as the aircraft flies under their AOC and operating manuals. The client airline still has responsibility for its own commercial conduct and for choosing a credible operator.

7. Is ACMI the same as charter?
No. Charter is usually sold by a broker or operator directly to a client for a specific mission. ACMI is capacity sold to another airline to operate its scheduled or charter network.

8. What are the main risks for the client airline?
Dependence on a third party for capacity, exposure to service failures, higher unit cost than own metal in the long run, and the risk of contracting with weak operators who cannot deliver.

9. What are the key risks for ACMI operators?
Payment risk from airlines, operational disruptions, crew shortages, and thin margins if minimum hours are not achieved or fuel and handling terms are badly negotiated.

10. How should an airline choose an ACMI provider?
Check AOC and safety record, financial strength, fleet age and configuration, on-time performance, crew availability, references from other airlines, and contract terms around dispatch reliability and penalties.

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