Updated: Nov 22
Fatigue is one of the most critical aspects to consider in any shift work design process since it is a potential risk factor for human error. Most research related to human fatigue in the aviation industry targets pilots, yet Air Traffic Controllers also experience elevated levels of fatigue that can affect aviation safety. Despite this, fatigue is often overseen as it is a mental and physical status that is difficult to measure.
Fatigue can have a significant impact on an ATCO's ability to make timely, accurate, and correct decisions – so it is crucial that all Air Navigation Service Providers take steps to minimize the risk of fatigue affecting controllers and their operations. The fatigue induced by inappropriate scheduling (rostering) is a worldwide issue.
1. What is Fatigue in Air Traffic Control?
Fatigue is a physiological state like hunger and thirst that cannot be suppressed. It is a signal that alerts us that we need to rest. Fatigue can affect performance and impair mental alertness, which may lead to dangerous errors.
In terms of its volume and chronicity, fatigue can be temporary (i.e. which can be removed by resting or sleeping) or chronic (i.e. building up over a long term and harder to get rid of).
There are three types of fatigue: mental, visual, and physical. Operational Air Traffic Controllers are mainly affected by the first two types i.e; mental and visual fatigue. For people with engineering, maintenance, or driving roles, for example, managing physical fatigue is a high priority, but for an air traffic controller who is processing and communicating information while working in front of a radar screen or looking out of an airport control tower window, managing mental and visual fatigue is important.
2. Recognizing signs of fatigue
Fatigue can come on quite quickly after a period of working, in which case the symptoms can be easier to detect. Alternatively, it can build up slowly and the Air Traffic Controllers may not necessarily recognize that they have become fatigued. Here is the list of a few important signs to recognize different types of fatigue:
Subjective feelings of weariness, sleepiness
Reduced ability to concentrate and pick out important information
Poorer judgments / increased carelessness
Slower decision making/reaction times
Less likely to detect errors – both your own and other people's
Pain/irritation/burning sensations in one or both eyes
Difficulty in focusing/double vision
Reddening of the eyes
Physical symptoms such as aching muscles
Feelings of weariness, need to sit down/rest
Awareness of Operational staff of fatigue:
Often there may be early tell-tale signs of fatigue in air traffic controllers, for example:
• Missing pilot calls or read-backs.
• Forgetting routine tasks (such as strip marking or transferring an aircraft to the next sector).
• Starting to fall behind in planning.
As fatigue becomes more severe, the warning signs could be more obvious:
• Missing an aircraft when planning from the radar due to narrowed attention.
• Confusing the steps of a plan, possibly changing a plan repeatedly.
• Missing warning indications.
• Impaired teamwork or leadership – not communicating well with colleagues or taking longer to tell others what to do.
• Finding it harder to concentrate on the ATC situation and being more easily distracted.
• Irritability - pronounced irritability and moodiness very often triggered by routine tasks or any other minor stimulus.
Operational managers or supervisors are in a good position to look out for signs of fatigue in their staff and will also be the person who may need to support staff showing symptoms of fatigue.
Although performance can change for other reasons, it is always essential for a manager or supervisor that detect one or more of the above to explore whether fatigue may be involved. They need to be prepared to take appropriate steps to give the air traffic controller an opportunity to rest.
3. How is fatigue measured?
The fatigue-detecting methods for ATCs can be divided into subjective and objective methods. A popular subjective method is the internationally recognized Samn-Perelli scale, where individuals rate their level of fatigue on a scale of 1 to 7. A score of 1 indicates that the controller is fully alert and wide awake, while 7 indicates that they are completely exhausted and unable to function effectively. In any safety-critical role, there should be no scores above five.
4. What are the main factors that influence fatigue?
The rapid development of civil aviation results in continuing increases in the volume of air traffic in the world. Despite the rapid growth in the number of flights, the growth rate of the number of ATCs (air traffic controllers) is relatively slow. The associated increasing working pressures are making ATCs more susceptible to fatigue.
Sleep is vital for your body to rest and repair as well as to give your brain a chance to ‘sort things out ' – it is thought sleep may be the time when the brain organizes and stores information, replaces chemicals, and solves problems. A lack of good quality sleep will affect you. Most people require between 7 and 8 hours of good quality sleep within each 24-hour period.
Prolonged mental or physical exertion due to inflexible shift work rostering leads to unbalanced workload and ultimately fatigue, which can affect ATCO’s performance and impair their mental alertness.
Lack of good quality sleep and illness can also cause fatigue. ATC is a 24/7 operation. Individual controllers make thousands of important decisions every day to ensure aircraft are safely separated and routed efficiently. The role relies on quick thinking and clear communication, and it is crucial that controllers remain at their peak performance at all times, especially in the middle of the night when their bodies are telling them that they should be asleep.
In the past, some of the most tiring schedules required controllers to work up to five straight midnight shifts, or to work six days a week several weeks in a row, often with at least one-midnight shift per week. The human body's circadian rhythms make sleeping during daylight hours before a midnight shift especially difficult. The current practice is to work for maximum three consecutive night shifts to reduce the risk of fatigue.
Studies have shown that humans are more likely to make mistakes when they have either very high or very low workloads. During night shifts when generally there is less traffic to control and hence workload is low, it is very important to keep controllers alert.
5. Ways to minimize fatigue: high-performance shift rostering
Operational Air Traffic Controllers are susceptible to fatigue as they need to sustain accurate task performance over a shift period. As they typically work shifts, there will be times within the shift when they will need to maintain alertness when their natural circadian rhythms are making them drowsy. With careful lifestyle management outside work and fatigue management within the workplace by a flexible rostering, operational staff would be able to manage fatigue risk successfully.
It is very important to achieve a good balance between work and social life in order to minimize the risk of being fatigued when at work. Working as an Air Traffic Controller requires you to sleep enough to be fit to perform at an acceptable level of alertness when on duty. A flexible shift work rostering system that distributes workload equally, integrates working preferences and keeps track of each employee's fatigue index becomes vital in this endeavour.
Rostering automation must enforce proper resting and recovery times and promote swift change of shifts. It also promotes smooth shift swapping to get more recovery if required. Doing manually this kind of rostering is a very time-consuming, error-prone, and complex task to achieve. Skyroster is an easy-to-use, easy-to-deploy solution to most of these problems, which assists shiftwork planners with their day-to-day high-performance rostering. Check the SkyRoster Free Plan Subscription and evaluate it based on your specific needs.