It’s not new information: fatigue reduces a maintenance technician’s ability to perform safety-sensitive work. The truly insidious part is often technicians don’t notice they’re fatigued and as such primed to make a mistake.
On the center stage at the Vertical MRO Conference in Kelwona, B.C. last month, Pulsar Informatics vice president of customer success Meredith Hedwell and lead program manager Doug Downey broke down fatigue, its common causes, and how technicians and supervisors can both identify its potential and take action to control it.
Downey started by associating the process with a procedure familiar to helicopter maintenance professionals. Aircraft are checked by onboard diagnostics before, during, and after maintenance. However, no comparable check exists for the technicians doing the work. “Fatigue should be monitored and managed with the same discipline we apply to our aircraft systems,” he argued.
Diagnosing Fatigue
Hedwell defined fatigue as a physiological state of reduced mental or physical performance, which is very different from just ‘feeling tired.’
“You can be very, very tired and not fatigued,” she explained. “You can be fatigued and not feel tired.” she said. She explained fatigue does not always produce a noticeable sensation such as ‘tiredness,’ making it difficult for technicians to rely on how they feel to judge whether they are fit for a task.
The effects of fatigue are similar to those of alcohol, she explained. Fatigue slows response times, causes lapses in attention to detail, leads to impulsive decisions, alters how people perceive risk, reduces situational awareness, and makes it harder to change strategies when a task is not going as planned.
“Fatigued technicians make more errors and have poorer memory,” Hedwell said. “Their mood may also change, which coworkers often notice before the technician does.”
It can even cause microsleeps, which occur when the brain’s region responsible for promoting sleep steps up. A lapse of half a second can go unnoticed by the person experiencing it. Yet that half second can be hazardous during tasks that require sustained focus, such as engine work or a borescope inspection.
Fatigue is so prevalent in its effect on safety it runs through the entire Dirty Dozen, Downey explained. “There’s an element of fatigue in every single one of them,” he said of the Dirty Dozen risks to aviation safety.
While it’s good and well to know fatigue is an issue, and assign elements of it to accident and incident causes, the reduction of fatigue in aviation maintenance operations can only be reduced by digging deeper into root causes, not assigning blame, Downey emphasized.
The Causes of Fatigue
Hedwell identified three primary tangible root causes of fatigue that can be directly addressed – sleep debt, long duty periods, and time of day.
Missed sleep accumulates, creating a sleep debt that can only be paid off with sleep, she explained. Individual sleep needs vary with about 15% of people needing roughly six hours, while most need seven or more, and some on the other side need nine or 10. A strong way to determine your sleep needs is through a wearable device such as a watch, band or ring that tracks your sleep and other biometrics, or by taking careful note how you feel after different amounts of sleep, Hedwell said.
When it comes to duty periods, people are suited to about 16 hours of awake time a day to do everything from eating, errands, travel to and from work, daily restorative time, and other obligations in addition to work. Long shifts leave less time for those other obligations, which can then cause reduced time for sleep.
The time of day a technician is working can also have a significant impact on fatigue. Working at night runs against the body’s circadian rhythm of working during daylight hours. Hedwell also highlighted the window of circadian low, which runs from roughly 2 a.m. to 6 a.m. depending on the person, shifting by about an hour for early or late sleepers. Sleep during this period is the most restorative to combat fatigue. While night shift work cannot be avoided at most maintenance operations, she recommended planning shifts where technicians can sleep for at least part of this window whenever schedules helps reduce fatigue.
The effects of fatigue compound when these causes occur together.
“It’s not like one plus one is two,” Hedwell said. “It’s like one plus one is five.”
Combatting Fatigue
The good news is, even for night shift maintenance professionals, there are several things you can do to combat fatigue before it becomes an issue.
The first is allowing time to overcome sleep inertia, the grogginess that follows waking. Especially when waking during the window of circadian low, it can take time to become fully awake. Bright light, physical activity, caffeine, a shower or cold water on the face can shorten the effect before safety-sensitive work begins, Hedwell said.
Increasing sleep quality can also make a noticeable difference. Sleep in a quiet, dark, and comfortable environment for optimal sleep quality, Hedwell said, and avoid blue light from screens an hour before bed as blue light mimics sunlight, triggering the brain to stay awake.
Caffeine postpones the effects of sleep debt but does not remove them, and alcohol and sleep aids reduce sleep quality, she added. Consistent routines also help. Hedwell recommended eating meals at regular times, limiting fluids before bed and avoiding exercise within five hours of bedtime. Blue light blocking glasses with orange or red lenses can help as well, she added, stating clear “blue light blocking glasses” only help with eye strain, not actually blocking the blue light.
Downey emphasized actions by supervisors and maintenance organizations can also add to fatigue. Pressuring technicians to hurry can cause stress and skipped steps, not maintaining opportunities for technicians to maintain proficiency on key requiring considerable focus increases risk for a mistake, and not monitoring maintenance teams’ alertness can lead to missed signs of fatigue.
“Fatigue comes in many forms,” Downey said, when he suggested leaders communicate with their teams to identify fatigue. “Rest is one factor, but so is emotional fatigue, personal issues, the end of a work week, and the end of 12-hour shifts.”
Measuring and Predicting Fatigue
Hedwell and Downey suggested a psychomotor vigilance test (PVT) can be valuable tool in identifying fatigue. A brief reaction-time test that detects the lapses in awareness caused by fatigue, a PVT administered to a technician who then misses prompts on the screen without realizing it, will flag fatigue. The test can be paired with a model that uses work schedules to predict when each person on the team will be most fatigued, allowing organizations to adjust schedules in advance.
Some organizations even use a passing PVT result as a condition for approving extended overtime, Hedwell said.
Downey closed the presentation by encouraging technicians to raise fatigue openly.
“The most effective solutions come from the people doing the work,” he said.
The Irving Vertical MRO Conference will take place in Irving, Texas, Nov. 16-18 with a schedule packed with sessions covering leadership skills, hands-on training, industry issues, safety, workforce development, increasing maintenance efficiency, and more with most session qualifying for FAA IA renewal credit.
To learn more about the Vertical MRO Conferences, view the schedule for Irving, and to register, visit verticalmro.com.