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Fatigue is a major health and safety concern across industries. OSHA’s worker fatigue webpage states that working 12 hours per day is associated with a 37 percent increased risk of injury. Health problems such as heart disease, stomach and digestive problems, and musculoskeletal disorders are all associated with fatigue. The consequences of fatigue are especially critical in aviation, as sleep-deprived pilots may experience memory problems and have decreased ability to think and react quickly. A paper in the Journal of Aviation Technology and Engineering (PDF) reported that 15 to 20 percent of the fatal aviation accidents attributable to human factors are directly caused by crew fatigue.

Julius Keller, PhD, a certified flight instructor and associate professor at Purdue University, thought it likely that an even greater proportion of aviation accidents may result from fatigue. He explained that very specific information, such as hotel key card activity, text message timestamps, and behavioral observations, is required for an accident report to state that a person was fatigued. “Oftentimes, it’s hard to get into people’s minds at the moment of an accident or incident,” he said. “So, we estimated that it’s probably a little bit higher.”

Even when pilot fatigue doesn’t result in fatal accidents, it may lead to errors, near misses, and increased sick days. For that reason, Keller and his colleagues are researching the impacts of fatigue in aviation. What they’ve found has implications for high-reliability organizations in other sectors.

Gathering Data on Pilot Fatigue

As a pilot himself, Keller is familiar with the operational aspects of fatigue. Much of his work focuses on improvements for collegiate flight programs, an area that is underrepresented in fatigue research. “A few years ago, we were looking at the literature, and collegiate aviation pilots were left out of the discussion,” he said. “Most of the research was done on airline pilots, as well as military pilots, so that was a gap that we wanted to address.”

To better study the effects of fatigue on collegiate pilots, Keller teamed up with Debra Henneberry, EdD, a fellow flight instructor, emergency medical technician, and assistant professor at Purdue’s School of Aviation and Transportation Technology, as well as Mark Wilson, PhD, a clinical assistant professor in the School of Health Sciences. They found they had to start almost from scratch because the research needs for the collegiate pilot population were so different from those of better understood populations. Over time, they developed research methods that fit their purposes.

One challenge was that of measuring fatigue objectively, something Henneberry explained has been difficult in the past. “We’ve always done this subjectively, as a self-assessment,” she said. “We used acronyms to check ourselves, but there’s a lot of bias that we have to work around.”

This expertise was provided by Wilson, who has a master’s degree in industrial hygiene and a PhD in public health. He teaches courses in Purdue’s occupational and environmental health sciences program. Wilson is also familiar with the wide range of wearable sensors that have become more accurate, specialized, affordable, and easier to use in recent years. “My experience with aviation is limited, other than being a passenger,” he said. “But I’ve had an interest for quite some time in stress and fatigue and have worked with measures like heart rate variability and how that informs us about stress and fatigue.”

The team started out using subjective measures to track aviation students across the semester, then introduced wearable sensors to collect objective data. In addition to biometric information such as heart rate, the sensors measured environmental factors such as noise, vibration, and temperature that are believed to affect pilot fatigue, performance, and health, although researchers aren’t yet sure how and to what extent. These findings were used to improve Purdue’s pilot training program.

But while the data has proved useful, the collection process was cumbersome. “Getting all this data at the same time, working around the schedule of a busy flight department, and trying to get the right students at the right time, that’s been a lot for us,” Henneberry said. “We’re managing, we’re getting it done, but we’re always interested in sharing and receiving feedback from others on how we’re doing this.”

The Strengths of Collaboration

The project undertaken by Keller, Henneberry, and Wilson was founded on interdisciplinary collaboration, and collaboration will be critical to their next steps. When the three share their findings at AIHA Connect 2026 in June, they hope to receive tips and suggestions about data collection and fatigue management from their audience. They also hope their work will provide guidance to professionals in other fields and industries.

As Wilson pointed out, fatigue is a problem in almost every industry, not just aviation. But the impact of aviation accidents makes fatigue assessment and management particularly important in that industry. “What we’re doing with aviation can certainly inform other industries,” he said. “It’s good to share practices and get people together from different perspectives, different industries, to see what everyone’s doing because that’s where you can learn about techniques or knowledge that you weren’t aware of in the first place.”

He also hopes the AIHA Connect presentation—“What Aviation Teaches Us About Fatigue and Performance”—will introduce the aviation industry to a wider audience of occupational and environmental health and safety professionals. “This really demonstrates cooperation and partnership between industrial hygiene and an industry that hasn’t been at the forefront of occupational health and safety,” he said.

“I think aviation is often siloed from other disciplines, which is bad for both aviation and other disciplines that can learn from aviation,” Henneberry said. She observed that her and Keller’s work is influenced by industrial health and psychology, which also inform high-reliability organizations in other fields. Their findings have begun to identify red flags for situations that are particularly fatiguing or stressful for pilots, which may be applicable to workers in other industries. “For scheduling and team management, I’m hoping that we can inform a lot of other disciplines with what we find out.”

For Keller, his aim isn’t just to study health effects but to make sure his students are better prepared for their future careers as pilots. Historically, the profession has sometimes resisted research on pilot fatigue and stress, but this is changing as individuals, employers, and the Federal Aviation Administration increasingly recognize the importance of mental health. Keller hopes that both individuals and organizations will adopt the lessons learned over the course of the project. “Overall, it’s a win-win,” he said. “If individuals are informed of what their metrics looked like and how these environments impact them, they’re more likely to prepare better, make better decisions, and hopefully reduce errors.”

Julius Keller, Mark Wilson, and Debra Henneberry will present “What Aviation Teaches Us About Fatigue and Performance” on Tuesday, June 2nd, from 10 to 11 a.m. AIHA Connect 2026 will be held June 1–3 at the Ernest N. Morial Convention Center in New Orleans. To view the conference agenda or to register, visit aihaconnect.org.

Resources:

AIHA: “Fatigue Management Learning Pathway.”

Journal of Aviation Technology and Engineering: “Fatigue and Its Management in the Aviation Industry, with Special Reference to Pilots” (PDF, 2021).

OSHA: “Long Work Hours, Extended or Irregular Shifts, and Worker Fatigue Hazards.”

The Synergist: “Deciphering Fatigue Risk Management Systems: A Holistic Approach to Mitigating Work-Related Fatigue” (October 2022).