Stepping Down Fatigued or Not: What Makes Flight Crews Decide to Step Down From Duty.

Sammanfattning: With the emergence of industrialisation, the work-life balance has become a point of discussion in many industries, among which the aviation industry. Distortions in the work-life balance became especially apparent when 24/7 economies evolved, and industries made a transition to facilitate and serve these economies. Incidents and accident have since then been related to fatigue more than before. The aviation industry and regulators have so far primarily attempted to deal with this imbalance via prescriptive rules and guidelines based on hours-of-service principles, post hoc measurements, and reports. Science in the meantime, pointed out that fatigue, especially in complex environments, can be related to a large number of factors of influence. So far, however, this has not resulted in shifts in regulative approaches. In the end the regulations remained focused, primarily, on the measurement of quantitative, and almost purely physiological, aspects of fatigue. Unknown, however, is, for instance, whether these measurable factors of fatigue always result in individuals being (or experiencing) fatigued, whether these measurable and regulated aspects could hold as the norm for everyone, and whether the decision to step down fatigued is always and with everybody based on the same factors? This study attempts to provide some answers to these question through the acquiring of an in-depth understanding of the individual process of crew members in their decision to step down. The study started with a literature study into the phenomenon of fatigue, elaborating thereby especially on what aspects are fatiguing or may contribute to recovery from fatigue. Thereafter, a field study has been performed among flight crews to get insight in how they deal with fatigue, how the aspects of fatigue are weighed, and how they come to a decision whether to step down. The conclusions drawn after analysis are that fatigue is more than the summation of fatiguing factors. Furthermore, the pre-decision process and the final decision whether to step down is mainly based on individual experiences and assessment. Finally, the interaction between and interdependencies of the influential factors of fatigue, in combination with the context at the time of the decision-making process, make that the individually made decision is very hard to predict.