Motulus pride themselves on pioneering and innovative approaches to solving aviation challenges. This article explores the first challenge Motulus looked at in challenging the status quo in crew rostering: integrated crew scheduling.
Crew planning is a complex process that has driven the development of sophisticated automation and optimization tools over the past 40 years. The approaches to preparing plans do, of course, vary across different airlines but a consistent process has evolved across the industry that is now found, as a framework, in many carriers.
The process often involves two intricate optimization steps. First, chunks or blocks of work are created. Several flights are combined into an efficient sequence, sometimes including overnight stays, sometimes not. These blocks of work always start and end at a home base. While this may sound simple, with hundreds of potential combinations, only sophisticated mathematical algorithms can find the optimal solution.
The second step allocates these blocks of work to crew members. These rosters (also known as schedules), which can span one, two, three, or even more days, are built around existing duties (also known as pre-assignments), vacation days, training, or meetings. Once again, the problem involves managing many complex combinations.
When Motulus first began to approach crew planning optimization challenges in 2018, they quickly encountered an issue. The perfectly optimized pairings often didn’t fit within the rosters. The two optimization approaches did not produce a global optimum, leading to overall inefficiencies across all of the rosters. This could happen for various reasons: sometimes, crew groups had so many pre-assigned activities that the pairings were no longer efficient. Pre-assigned activities could be training or vacation duties that have been allocated to individual crew rosters in advance. A crew group could be large or small, based at a base, or composed of trainers from different locations. It could be that for most of the planning period (typically a month) the availability within a crew group would be sufficient, or the flight plan for that crew group changed for just a few days within a month. In summary, unstable demand and supply within sub groups of the crew community led to the pairings (prepared by a separate optimization step) being unfeasible.
The inefficiency in the overall approach was evident. Pairings would often have to be broken up and reworked manually, with crew planning teams under time pressure to fit them back into the rosters. As a result, the perfectly optimized pairings were no longer optimal.
Motulus recognized the need to integrate these two optimization processes into one. Historically, this concept had been reviewed but never implemented at an industrial level, usually due to the lack of computing power or mathematical techniques capable of integrating flights directly onto rosters for large-scale problems. However, Motulus had significant expertise in advanced mathematics and high-performance computing and were confident they could solve this problem: which they did!
Motulus developed an integrated scheduling approach whereby only one optimization run would be needed to create rosters. Sometimes called leg based rostering the Motulus optimization product (MCrew) would generate rosters based on a flight programme (such as a SSIM file) as an input. All other key rostering features (fairshare, recency, fatigue calculations, crew requests) would still be respected. The benefits were clear. The ability to build rosters based on this lower level of granularity reduced positioning costs, hotel costs, increased crew request satisfaction. Significant process improvements could be seen with this ‘one click’ optimization approach. The end to end roster production time reduced.
MCrew is in production now at several European airlines that vary in size and have different operating models: from one to many bases, long and short haul operations and so on. If you would like to explore the potential benefits integrated crew scheduling could bring to your organisation then please reach out to us at contact@motulus.com.
Photo by Matt Ridley on Unsplash
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