November 25, 2022


Sofema Aviation Services (SAS) considers the process by which the Fatigue Risk Management System can minimize the exposure to fatigue by identifying and mitigating Fatigue Risk within the MRO workplace.

Introduction Considering Different Types of Fatigue Drivers

There is often no clear distinction between these types of fatigue, and it is probably more useful to look at fatigue in terms of the various criteria by which it is recognised.

  • Physical Fatigue (Example – Muscle soreness, tiredness caused by sleep deprivation, illness or poor nutrition),
  • Mental Fatigue (Example – Tasks demanding intense concentration, rapid or complex information processing and other high level cognitive skills),
  • Emotional Fatigue – Example Working under trying environmental conditions or performing psychologically challenging tasks).

Whilst fatigue to a large extent involves a degree of subjective interpretation, indirectly it is possible to assess Fatigue through its effects and outcomes.

  • For example, we can measure the number of errors committed per unit time on a particular task.

o Time on task increases the likelihood that the person doing a particular task (without rest) will see an increase in the number of errors.
o Therefore it is reasonable to conclude the person is suffering from fatigue

Note – Working long hours, working night shift (during normal sleep hours) as well as working on rotating shift patterns may all produce various fatigue-like effects

What are the Symptoms of Fatigue?

  • A lack of awareness;
  • Diminishing motor skills;
  • Diminished vision;
  • Slowing reactions;
  • Short-Term memory problems;
  • Over fixation on potentially unimportant issues;
  • Easily distracted by unimportant matters;
  • Increased mistakes;
  • Poor judgement;
  • Poor decisions, or no decisions at all;
  • Mood Swings – abnormal moods – erratic changes in mood, depressed (may be periodically elated and energetic);

Fatigue Mitigation Management Guidance

Individuals should be fully aware of the dangers of impaired performance due to any potential fatigue related factors and to take note regarding their own personal responsibilities.

  • Tiredness and fatigue can adversely affect performance.
  • Excessive hours of duty and shift working, particularly with multiple shift periods or additional overtime, can lead to problems.

Reduce or Minimize Fatigue with the following actions

The impact of fatigue may be minimized by simplifying the night shift workload wherever possible and bolstering the day shift critical tasks, Introduce additional Quality Control Checks to support Night Shift Activities.

  • Avoid excessive working hours;
  • Enable as much regular (normal) night sleep as possible;
  • Minimising sleep loss;
  • Provide an opportunity for extended rest whenever night sleep has been disrupted;
  • Factor in to planning activities reduced physical and mental capacity when working at night;
  • Where relevant be prepared to taking into account individual circumstances (provide organisational support services);
  • Provide opportunity for fatigue recovery;
  • Consider the feasibility of rotating shifts toward the biological day (rotate to later rather than earlier shifts);
  • Minimising night shifts through creative scheduling;
  • Providing longer rest periods following night shifts;
  • If more than 2 night shifts within a week enable longer continuous rest periods.

Next Steps

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Sofema Aviation Services ( and Sofema Online ( offer Classroom, Webinar and online training covering all elements of EASA Part 145 Approval including Quality, Safety & Production Planning including the Development & Management of Fatigue Compliant Organisational Systems. For additional questions or comments please email us at


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