Understanding Schedule Fatigue

Understanding the potential contributors to fatigue in your schedule is a key component of effective fatigue risk management. Whilst some large organisations have this capability in-house, bio-mathematical fatigue models can be expensive and require expertise to use effectively.

Our schedule analysis service can provide you with:

  • A one-off analysis of 12 months of your planned and worked schedules, to highlight key ‘hotspots’ of fatigue, the features that contribute to that fatigue, and the change from the plan to what was actually worked
  • Ongoing monthly analysis of your planned and actual schedules, to enable proactive fatigue risk management
  • Individual ‘case study’ analyses, for example, if you are considering changing a shift pattern, are investigating an event or incident, or as part of an internal or external safety case.

An analysis of the schedules can help you answer key questions:

  • What features of our planned and actual schedules are consistently contributing to elevated fatigue levels?
  • What is the impact of on-the-day delays or operational changes on fatigue?
  • How do fatigue levels change per month and seasonally?
  • Do our different bases have different fatigue profiles?
  • Are we continually improving?
  • What is the predicted level of schedule-related fatigue in a specific circumstance?

Assessing The Impact of Schedule Changes

One way in which bio-mathematical models can enhance FRM is by assessing the impact that changes to schedules or alternative schedule designs have on fatigue. For example, fatigue models can help to answer the following questions:

  • For my long-haul or ULR operation, how can we schedule crew in the days or weeks prior to maximise performance and minimise fatigue?
  • We are looking to change the shiftwork pattern in our organisation – how do the different options ensure that fatigue is appropriately managed?
  • What is the fatigue impact of delaying the start time of specific shifts or duties?
  • If I change the number of long-haul flight deck crew on an augmented flight, how will the changed in-flight sleep patterns impact fatigue levels at landing?
  • What is the best order in which to schedule a series of early starts or late finishes?


An analysis of your schedules to assess alternative scheduling options provides you with an in-depth understanding of the levels of schedule-related fatigue. We have extensive experience of using bio-mathematical models, and have developed a suite of metrics that give you a detailed assessment of schedule related-fatigue. Using these metrics, we can work with you to develop Safety Performance Indicators (SPIs) for schedule-related fatigue, for ongoing tracking within your FRM.