Navigating extended duties and sleep

Abstract

Aerial firefighting refers to the use of aircraft to combat wildfires, playing a critical role in wildfire suppression. These fixed-wing aeroplanes or helicopters allow for easier access to fires since they are less restricted by terrain and vegetation. As a result, they operate in high-risk, low-altitude environments and have a high fatality rate due to the complex manoeuvres needed in often turbulent, smoky, and congested fire environments, which often coincide with intense stress among pilots. Despite its importance, aerial firefighting has received little attention regarding its operational demands, as existing studies largely emphasise cost and effectiveness, with little to no research being done in the South African context. This underpins the first aim of this study, which was to characterise the working system of aerial firefighters to identify the risks and demands associated with aerial firefighting in South Africa. Like other emergency services, aerial firefighters are on-call and work away from home for extended periods since the key feature of these services is being ready to fly for low-probability events. These features of on-call work may impact the sleep-wake behaviour, which, when combined with the demands of the actual flying, may present risks for pilot fatigue, which in turn presents a risk to flight and public safety. Prior sleep-wake behaviour of individuals is measurable and potentially a verifiable factor influencing pilot fatigue. Thus, the second aim of this study was to understand the sleep-wake behaviour of pilots as part of the current fatigue risk management system. This study adopted a dual-phase mixed-methods approach to addressing these aims. This mixed-methods study used semi-structured interviews of four key stakeholders to characterise the work system and demands of aerial firefighting. Subsequently, sleep-wake behaviour was observed through actigraphy, Consensus Sleep Diary and the Pittsburgh Sleep Quality Index during 2021’s duty period (4-6 weeks on, 2 weeks off). A key finding of this study is that aerial firefighting is a precision-driven, high-stakes field requiring pilots to manage uncertainty through deep knowledge of environmental, fire, and operational risks. Key roles (Spotter, Bomber, Huey pilot) necessitate specialised competencies for hazard navigation, team coordination, accurate execution, and real-time adaptation. Task variability emerged as a central insight, reflecting the profession's evolving demands. Furthermore, most pilots achieved adequate sleep duration (>7 hours per night) and regular sleep, with 75% of pilots maintaining bedtime regularity (<60 min variation), and 83% had consistent wake times (<60 min variation) during the six-week duty period. Overall sleep quality, as rated by the PSQI (global score 4 ± 2.05) and sleep diary (3.80 ± 0.58), was positively assessed, with participants reporting good sleep quality. A notable finding was the elevated wake-after-sleep onset (WASO) in actigraphy data, and PSQI data reporting sleep disturbances as the major concern in pilots who were rated poor sleepers (n=3). Thus, this study found that most pilots sleep well on average during the six weeks of duty; however, there are a few pilots who are at risk with the current duty period. Thus, it is crucial to manage sleep and, by extension, fatigue risk on an individual basis alongside a one-size-fits-all fatigue management framework.