It’s easy to find case studies, articles, and examples of the crew planning challenges of traditional scheduled airlines. But while the research is abundant, the problem itself is anything but easy. Crew planning—also known as roster scheduling—is one of the most complex challenges in aviation. This is also particularly true for ACMI (Aircraft, Crew, Maintenance, Insurance) and charter carriers; they face a different set of rostering challenges but in this area the research is less well documented.
Most published studies and conference presentations focus on national carriers, low-cost airlines, or large scheduled operators, who work with established routes and networks. These operators face significant complexity—union rules, local agreements, regulatory constraints (FAA/EASA), and best practices all make scheduling a puzzle. However, their operations usually run from established bases with relatively predictable schedules.
By contrast, ACMI (Aircraft, Crew, Maintenance, Insurance) and charter carriers face a different set of rostering challenges.
The ACMI/charter business model is diverse and, at first glance, can appear simpler. These operators typically fly on behalf of other airlines or governments. Contracts may be:
This variability creates major planning hurdles:
As a result, crews may need to:
On top of that, ACMI operators often employ an international workforce, which adds complications around visa requirements and legal permissions to operate in multiple countries.
Pairings and Schedules
Scheduled airlines often build “pairings”—sequences of flights that start and end at a home base.
For ACMI, flight schedules can be simpler (one aircraft on a seasonal contract), but getting crew to the right place, at the right time, is the real challenge.
Crew Positioning
Operators must efficiently manage positioning flights to move crew between temporary bases.
Rosters must balance operational coverage with cost control.
Standby Coverage
A reliable pool of standby crew is essential, given sudden operational changes.
Days Off and Quality of Life
Days off are critical for all airlines but even more so for ACMI, since crew have less influence over where they operate.
Rosters must provide long, meaningful breaks, not just fragmented rest days, to ensure both compliance and crew well-being.
At Motulus, we’ve embraced the complexity of ACMI crew planning. Building on our expertise in conventional crew optimization, we’ve developed models that also handle the unique dynamics of ACMI and charter operations.
We use our sophisticated optimization toolkit to solve the ACMI challenge in three steps, all contained within one optimization calculation. Firstly we establish the core demand at each FTL or customer base: this is similar to a classic pairings calculation but considers days off requirements within each crew deployment to an operating base. The second set calculates the best allocation of crew to each base within each planning period; this step must consider operational and visa constraints, days off patterns as well as positioning restrictions and costs. Finally our algorithm will generate pairings and rosters for each crew member within each base; included in this step will be the generation of reserve or standby duties.
With our optimizers, we have demonstrated that it’s possible to:
We believe the ACMI world is fascinating, and we’re eager to engage with more operators to learn about their specific challenges. Our team thrives on solving tough problems that others haven’t tackled—and crew planning in ACMI is exactly that kind of challenge.
👉 If you’re an ACMI or charter operator looking to improve rostering, we’d love to talk.
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