ACMI Wet Leasing For Airlines: How To Secure Extra Capacity Without Buying Aircraft

Many airlines face the same problem every season: slots and demand are there, but the fleet and crews are not. New aircraft deliveries slip, maintenance schedules extend, and boards hesitate to approve further capital expenditure. In these conditions, ACMI wet leasing becomes a practical tool for protecting schedules and revenue without buying additional aircraft.

This guide is written for network planners, finance teams, and operations leaders who need to secure capacity in a controlled, contract-based way rather than through long-term ownership or dry leasing.

What ACMI Wet Leasing Actually Is

ACMI stands for Aircraft, Crew, Maintenance and Insurance. Under a wet lease, the provider supplies:

• The aircraft

• Flight and cabin crew

• Maintenance

• Insurance

The lessee typically covers fuel, airport and navigation charges, ground handling, and commercial activities such as sales and marketing.

Key characteristics:

• Flights operate under the lessor's AOC and operating procedures.

• Pricing is usually based on a per-block-hour rate with a guaranteed minimum block hour commitment per month.

• Terms can run from a few weeks to a season or a year, depending on the program and regulatory framework.

Per-hour cost often exceeds the ownership cost of a fully depreciated aircraft or a long-term dry lease, but the trade-off is flexibility and speed. Capacity can be added or removed without multi-year commitments and without placing large assets on the balance sheet.

Situations Where ACMI Wet Leasing Makes Sense

ACMI is not a casual tool. It is most effective when it prevents revenue loss, protects brand reputation, or preserves network integrity.

Typical triggers include:

Seasonal Peaks

Tourism waves, ski seasons, pilgrimage traffic, and major events can push demand above the base fleet's capacity. Wet-leased aircraft cover these peaks for a defined period while the core fleet continues with the regular schedule.

Fleet Shortages and AOG Events

Heavy maintenance, C-checks running over plan, late OEM deliveries, or unexpected technical issues can temporarily remove aircraft from service. ACMI covers scheduled routes while the affected aircraft are grounded, avoiding large blocks of cancellations.

New Route Launches and Market Tests

Airlines testing new route concepts or secondary markets may not want to commit scarce aircraft for a full season. Wet-leased capacity enables a trial period. If the route proves profitable, the airline can later switch to owned or dry-leased aircraft.

Start-Up Carriers and AOC Transitions

New airlines or operators going through AOC changes often use wet-leased aircraft to run initial commercial operations while final approvals, hiring, and internal systems are still being built. This approach protects launch timelines while reducing execution risk.

Cargo and E-Commerce Surges

Freighter ACMI has become particularly relevant for express and e-commerce operators faced with sharp, unpredictable peaks. Wet-leased freighters can support night networks or seasonal flows without committing to full-year capacity.

In each of these scenarios, ACMI acts as a pressure valve, absorbing volatility without forcing structural fleet moves.

How ACMI Wet Lease Pricing Is Structured

An ACMI quote is driven by the provider's fixed and variable cost base and the risk profile of the operation.

Core components usually include:

Block Hour Rate and Minimums

The headline number is the block hour rate, defined per scheduled block hour. Contracts almost always include a minimum guaranteed block hour level per month. If actual flying falls below that threshold, the lessee still pays for the minimum.

Positioning and Ferry Flights

Getting the aircraft into position and back out at the end of the program involves ferry sectors. These may be priced separately or blended into the overall commercial package. Complex positioning or repeated redeployments can move the economics significantly.

Crew and Base Costs

Crew per diems, accommodation, ground transport, and costs of operating from outstations are either folded into the block hour rate or itemised. Remote bases, night operations, or challenging rotation patterns can raise this element.

Extras and Disruption

Charges for de-icing, special ground handling, out-of-base maintenance support, and disruption-related repositioning should be defined clearly. Contracts that leave these items vague often generate disputes once operations begin.

A rate that appears far below peers often signals missing services, underpriced risk, or standards that do not match established operators.

Information Airlines Should Prepare Before Approaching ACMI Providers

The quality of offers from ACMI operators depends heavily on the clarity of the initial brief. A generic request such as "one A320 in Europe for summer" rarely attracts serious attention.

A professional approach includes:

Detailed Schedule and Block Hour Forecast

A full rotation plan with dates, sectors, block times, and expected monthly hours allows providers to check feasibility, crew pairing, and maintenance planning. This is the foundation for any realistic price.

Network and Airport Profile

The airport list, alternates, slot constraints, night curfews, performance-limited runways, and any special handling needs must be documented. High-demand airports, noise restrictions, and weather patterns all affect operational risk and cost.

Regulatory and Traffic Rights Overview

Cross-border wet leasing rules vary by region. Airlines need clarity on which authority must approve the wet lease, whether traffic rights are secured, and whether any bilateral or EU-specific restrictions apply. Providers will factor approval risk into their decision to commit aircraft.

Commercial Parameters

Preferred contract term, approximate block hour range, tolerance for seasonality, and any non-negotiable standards around punctuality, service, and branding should be outlined early. This helps filter out operators whose model does not match the requirement.

A structured data pack signals to the market that the airline is serious, organised, and capable of closing.

Contract Terms That Actually Matter

Once proposals arrive, contract details decide whether ACMI becomes a stabiliser or a source of ongoing conflict.

Areas that require close scrutiny:

Scope of Service

The agreement should state clearly whether it is full ACMI, damp lease, or some hybrid. Any deviation from the standard ACMI model must be defined in writing, including who provides cabin crew, who manages catering, and where responsibilities start and end.

Performance and Reliability

Dispatch reliability targets, delay thresholds, cancellation rules, and sub-service obligations must be spelled out. The contract should state the consequences if performance falls below agreed levels and how passengers are protected.

Maintenance and Downtime

Planned maintenance must be coordinated with the airline's schedule. For unplanned AOG events, the contract should set out replacement aircraft rules, financial compensation, and procedures for escalation.

Insurance and Liability

Cover limits, types of insurance, and responsibilities for passenger, cargo, and third-party claims must be crystal clear. Insurance gaps can create regulatory problems and reputational damage.

Crew Conditions and Safety

Labour standards, fatigue management, and contract terms for crew matter for both safety and public perception. Regulators and unions have already raised concerns where wet-leased operations rely on unstable or opaque crew arrangements. Airlines associated with such practices risk headlines and regulatory attention.

Regulatory Approvals

The contract should make all required approvals and ongoing compliance a condition, with clear provisions for what happens if approvals are delayed or withdrawn.

Payment Terms and Security

Deposits, prepayment structures, letters of credit, and any security arrangements influence risk on both sides. Vague or highly asymmetric payment terms often foreshadow disputes during disruption.

Well-structured ACMI contracts are explicit about which party carries which risk in every scenario that matters.

Running A Professional ACMI Sourcing Process

Even a mid-sized airline can run a disciplined, repeatable ACMI sourcing process without turning it into a mega-tender.

A practical approach:

• Shortlist established ACMI carriers and specialist lessors with visible fleets, credible oversight, and a history of on-time performance.

• Issue a consistent data pack to all candidates so that each provider prices the same schedule, airports, and conditions.

• Check real availability and lead times, especially for peak summer in Europe and high-demand cargo periods, where capacity is tight.

• Compare not only the hourly rate, but also downtime provisions, performance commitments, crew standards, and disruption rules.

Specialist brokers such as Blue Cube Aviation can help airlines translate operational requirements into a structured mandate and then approach a curated pool of operators, rather than sending generic emails into crowded inboxes.

Red Flags When Selecting An ACMI Partner

Certain warning signs should prompt a hard pause, regardless of how urgent the capacity gap feels.

Examples:

• Hourly rates that are far outside market norms without a clear explanation in terms of aircraft age, configuration, or risk.

• Evasive responses about AOC, safety record, or regulatory oversight.

• Lack of transparency on crew contracts, fatigue management, or working conditions, especially in light of ongoing scrutiny from European regulators and labour groups.

• Contracts that blur operational responsibility or fail to define who decides during disruption.

ACMI is not just about renting a machine. It is about entrusting an external operator with a brand, a passenger promise, and regulatory exposure.

Why ACMI Wet Leasing Remains A Strategic Tool

Handled well, ACMI wet leasing allows airlines to:

• Protect schedules during seasonal peaks and fleet disruptions.

• Test new routes and concepts without long-term fleet bets.

• Launch or relaunch operations while internal structures are still stabilising.

• Respond to cargo and e-commerce surges with targeted freighter capacity.

ACMI is not a cheap substitute for sound fleet planning, but it is a powerful complement. Airlines that treat it as a structured, contractual tool rather than a last-minute rescue tend to secure better aircraft, better crews, and better economics over time.

Airlines, charter operators, and cargo carriers planning ACMI programs or needing structured cover for peak seasons, start-up launches, or unexpected fleet gaps can work with specialist brokers such as Blue Cube Aviation, which screens operators, matches route and fleet requirements, and coordinates negotiations so that capacity, contract terms, and operational standards are aligned with the client's network and risk profile.