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The Human Factor

How The FAA’s Medical and Human Factors Research Helps Aviation

FAA Safety Briefing
Cleared for Takeoff
7 min readJan 3, 2022


By James Williams, FAA Safety Briefing Magazine

Photo inside cockpit simulator.
Engineering Psychologist Dr. Ian Johnson, FAA Weather Research Branch, and former human factors engineer. Read more about Johnson at:

What’s the one thing that runs through all aspects of human endeavor? The human. Whether the human performs or doesn’t dramatically impacts the outcome and safety of virtually everything we do. Paradoxically this becomes even more important as systems become more automated. A pilot’s human performance is key to a safe national airspace system (NAS). That’s why the FAA’s Office of Aerospace Medicine runs research labs focused on both human factors and medical research.

The Fatiguing Nature of Fatigue

Fatigue has been a scourge on every facet of aviation from its inception. Whatever role you play in the system (pilot, maintainer, dispatcher, etc.), fatigue reduces your performance and creates risk in the system. But what’s the difference between just being tired and being fatigued? And how could you tell if you are dealing with acute fatigue or chronic fatigue? Being tired might result from staying up too late to watch the end of the game, while acute fatigue might result from a busy week at work. Chronic fatigue is likely the result of an ongoing issue, whether professional, medical, or personal. The solutions to each of these conditions are different so understanding the difference between them is critical.

And that’s been the challenge. Fatigue is hard to measure beyond simply asking the subject directly. It can be hard to spot the differences between these states or even identify fatigue, even with willing people. If a person is used to only sleeping five to six hours per night, they may not realize they are operating at a deficit. Because everyone is different and has different sleep needs, and this changes throughout life, diagnosis is a challenge. If someone has become accustomed to being fatigued, what they are experiencing is “normal” for them, and they are unlikely to mention it to a doctor.

Defining the Indefinable

The question with a condition like chronic fatigue is how do you detect it, especially when the person may not even know that their condition is chronic and that they need to report it to a doctor? That’s where a more indirect approach may be helpful, and biomarkers can play that role.

Photo of researcher.
Vicky White loads samples for extraction of genetic material from blood, a first step in the measurement of gene expression biomarkers.

Biomarkers are measurable biological characteristics that can serve as indicators of some phenomenon, such as disease, infection, or environmental exposure. Comparable with measuring the height of a building by observing its shadow and calculating the angle of the sun, biomarkers allow you to detect or measure something that you may not otherwise be able to do. Biomarkers have a variety of applications and could be a strong indicator of a condition like chronic fatigue, which lacks a standardized laboratory test. For those suffering from fatigue, having a reliable indicator would be a powerful tool for getting treatment. And for those in industries like aviation, any kind of objective early warning system would be invaluable in the number of lives it could save.

Several organizations, including the FAA, have been pursuing this research for some time. In 2015, units of the National Institutes of Health (NIH) held a conference titled Developing Biomarker Arrays Predicting Sleep and Circadian-Coupled Risks to Health. The workshop brought together many researchers interested in finding biomarkers related to sleep. In 2016, a number of Japanese researchers published a paper that showed promise in using oxidative stress measures to discriminate participants suffering from chronic fatigue from those who were not. But more work was needed to define this biomarker.

In 2019, researchers from Stanford University developed a blood test that could accurately identify people with Chronic Fatigue Syndrome (CFS). While the study was small (40), the test detected the 20 participants with chronic fatigue without any false positives. The test works by measuring the participant’s blood to determine its immune cell response to stress. The immune cell response from those participants suffering from chronic fatigue will be different from those who are not. The hope is that this biomarker can rapidly test drug candidates by rerunning the test before and after exposing the blood sample to those drugs. This would allow initial testing of drugs with minimal risk to any human subject.

In 2021, Ohio State University announced the identification of the protein deoxyuridine triphosphate nucleotidohydrolase (dUTPase) as “a key modulator of the immune response that contributes to the immunological and neurological abnormalities in some individuals.” It suggests that dUTPase could be used as a biomarker of CFS, at least in a subset of patients. Ohio State is also working to develop a high-volume test that would allow for large-scale screening and early detection of chronic fatigue.

Photo of researcher.
Susan Munster views a pictorial representation of gene expression information, towards identification of genetic biomarkers related to aviation safety.

The FAA has been investigating fatigue biomarkers for a little over a decade. In particular, the FAA’s Functional Genomics Team within the Aerospace Medical Research Division is seeking molecular biomarkers associated with cognitive changes during sleep loss. The FAA published preliminary candidate biomarkers associated with attention impairment during sleep loss based on a collaborative study with Washington State University. Both ongoing studies and future planned investigations aim to improve and validate initial findings. Research is a highly detailed process, and vetting the results is both critical and time-consuming.

It’s essential to have as much research from as many angles as possible to develop the best possible metrics. Especially with a complex phenomenon such as fatigue that has a variety of health and performance implications, having more than one approach may improve management or treatment options. By working together with industry and academia, the FAA hopes to make fatigue a much smaller problem in the future.

Ergo Ergonomics

Another area in which the FAA’s Civil Aerospace Medical Institute (CAMI) has extensive research capabilities is in how humans work with aviation systems. Ergonomics is from the Greek word ergo, meaning work, and is the study of its efficiency. In more modern language, we’ve broadened the field to call it Human Factors, which is the study of how humans interact with their environment.

CAMI hosts two excellent labs dedicated to Human Factors Research: the NAS Human Factors Safety Research Laboratory (NHFS), which focuses primarily on Air Traffic Control and ATC systems, and the Flight Deck Human Factors Research Laboratory, which focuses on Human Factors in the flight deck.

Finding the Fit

The primary goal of the NHFS is to refine and improve the person-job fit for workers and organizations in the NAS through hiring, training, and technology. The lab explores all aspects of the work experience, from how the FAA screens applicants to developing air traffic procedures and systems. To that end, NHFS has a host of tools at its disposal, including ATC radar simulators, tower simulators, electroencephalography (EEG), eye-tracking systems, and more.

“Four years ago, I started a line of research about how controllers visually scan the air traffic environment to teach novice controllers, as well as experts, how to scan,” said Dr. Jerry Crutchfield, an engineering psychologist with the NHFS. “The scanning research led to my recent involvement in identifying visual requirements for remote tower systems.” It’s just one example of how NHFS research leads to ATC system improvements.

The FAA is uniquely positioned to have the in-depth technical knowledge of the systems involved, complete access to the operational data, and unparalleled access to the air traffic workforce for this kind of research. With change on the horizon in the aviation industry and in the NAS, having a world-class ATC Human Factors lab is critical to ensuring safety in the system.

Simulation to the Rescue

Photo of simulator.
Dr. Dennis Beringer tests out some eye tracking equipment in a simulator.

The Flight Deck Human Factors Research Laboratory (FDHF) looks at how Human Factors are associated with aviation accidents. FDHF benefits from having access to the FAA’s accident data, a large staff of skilled investigators, and simulator resources to replicate and test accident theories. FDHF’s dedicated team of researchers can reconstruct portions of an accident sequence and re-fly them to spot factors that may have contributed to the accident. One area that will be especially important for GA is how helper systems like wing levelers and auto-land capabilities integrate as they make their way to the market. Finding the right way to work these systems into GA will require much work and careful monitoring. It will be an iterative fault finding and fixing process that ideally suits the FDHF lab in assisting the aviation community. For more information on the NHFS and FDHF labs, see our July/August 2020 issue on Human Factors.

This article highlights just some of the many benefits the Office of Aerospace Medicine’s research capabilities provide to the aviation community, particularly the GA community, with a world-class research capacity normally reserved for large universities or commercial organizations.

And its research is focused on one thing — making aviation safer.

James Williams is FAA Safety Briefing’s associate editor and photo editor. He is also a pilot and ground instructor.
This article was originally published in the January/February 2022 issue of FAA Safety Briefing magazine.
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FAA Safety Briefing
Cleared for Takeoff

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