A tool for monitoring air traffic controllers’ fatigue

A tool for monitoring air traffic controllers’ fatigue

The Fatigue Monitoring Tool developed by Deep Blue has initially been validated in two pilot studies at ENAV in Italy, and will soon be released in its final version.


Effective monitoring and management of fatigue represent essential components within the science of Human Factors, aimed at mitigating the probability of errors and upholding optimal safety standards across organisations. This is true in a wide range of companies characterised by very long and tiring shifts alternating day and night work. Whether it pertains to transportation and distribution, manufacturing and logistics, critical infrastructure, public services, emergency response, or the healthcare system, the management of physical and mental fatigue assumes great importance in reducing the likelihood of accidents, injuries, and health-related challenges.

This is particularly true in the Air Traffic Management (ATM) sector, and that is why European Regulation 373/2017 by the European Commission addresses topics such as stress, fatigue, and the prevention of the use of psychoactive substances among air traffic controllers (ATCs).

But let’s go in order: what does fatigue represent from a Human Factors perspective? And more specifically, how are stress and fatigue meticulously managed and monitored in the domain of air traffic control?



Fatigue is defined as a physiological state of reduced mental or physical performance capability to safely operate, and can impair a crew member’s alertness and ability to safely operate. It can be caused by prolonged effort, lack of sleep, or excessive workload. It has also been shown that operators are more easily fatigued when performing hectic, repetitive, and monotonous tasks.

In fact, excessive fatigue results in slower reactions, reduced cognitive abilities (such as information analysis, decision-making, and memory retention), distractions, decreased vigilance, attention lapses, underestimation of risks, and impaired motor skills. Consequently, fatigue can lead to serious errors and accidents, as well as worsened health conditions and lower productivity. As reported by the Health and Safety Executive (HSE), among the major incidents and disasters where fatigue has played a decisive role are the Herald of Free Enterprise, Chernobyl, Texas City, Clapham Junction, Challenger, and Exxon Valdez.



The correlation between stress, fatigue, and performance within the air traffic control profession has been widely acknowledged. As explained by Professor Giovanni Costa in his 1995 article titled “Occupational stress and stress prevention in air traffic control “, air traffic controllers face a complex set of tasks that require very high levels of knowledge and skills, as well as the practical application of specific abilities related to cognitive domains (such as spatial perception, information processing, logical reasoning, decision-making), communication, and relationships.

Generally, the main causes of fatigue in the professional context can be attributed to two human characteristics:

  • Lifestyle, which includes the daily behaviours we engage in, such as physical activity, average hours of sleep, diet, workload, and level of effort required.
  • Human physiology, which refers to the natural potentials and limitations of the human body, including the sleep-wake cycle (or circadian rhythm) that plays a fundamental role.

These two factors influence each other, and together they can explain the majority of situations in which fatigue may occur.



In order to improve the management of stress and fatigue in Air Traffic Controllers (ATCs), European Regulation 373/2017 issued by EASA specifies in section 3 the “Requirements related to human factors for air traffic control service providers”. The aim is to prevent and mitigate the misuse of psychoactive substances, the negative effects of stress, and the effects of fatigue. Regarding the latter, EASA’s 373/2017 requires Air Traffic Management (ATM) service providers to implement a fatigue management policy for air traffic controllers and offer them specific information and prevention programs that also incorporate Human Factors.

With regards to fatigue management procedures, EASA suggests to Air Navigation Service Providers (ANSPs) a series of measures, including periodically reviewing procedures to ensure they remain relevant and appropriate.

To identify air traffic controller fatigue, EASA advocates the following initiatives:

  • Establishing and promoting the use of a procedure that allows air traffic controllers to report if they are fatigued.
  • Conducting surveys on perceived fatigue.
  • Applying scientific principles of fatigue and tiredness management and assessing their impact on the operational and organisational context.

Lastly, EASA fosters air traffic control service providers to develop, implement, and monitor a shift system to manage professional risks related to ATC fatigue, through a rotation of duty shifts and rest periods.



Deep Blue’s Fatigue Monitoring experts have directed their efforts towards examining the shift system of air traffic controllers, as highlighted by the data from the European Commission. “As soon as the new regulation issued by EASA integrating Human Factors into ATM Safety Management Systems came into effect, we conducted an initial analysis of relevant literature sources and benchmarked major European ANSPs on professional fatigue risk management”, states Michela Terenzi, cognitive psychologist and esteemed expert in Human Factors who leads Deep Blue’s Applied Human Factors Area.

The goal of the research was to identify the most effective parameters to be applied to the organisation of ATC shifts. Hence, Deep Blue’s experts analysed the guidelines and recommendations from EASA, Eurocontrol, and ICAO regarding air traffic management, and also drew from literature concerning shift work in different contexts such as the medical, railway, maritime, and industrial sectors. The findings were conveyed to ENAV, the company responsible for providing exclusive air navigation services in Italian airspace. In Italy, ENAV took charge of implementing and adhering to EASA’s 373/2017 regulation starting January 2, 2020, incorporating the insights gleaned from the study into the existing ATC shift system.



The implementation of the new parameters in the rostering is good and if better is possible, good is not enough! Monitoring is extremely important, as established in 373/2017 and as adopted in Italy by the National Civil Aviation Authority (ENAC), the Italian authority for technical regulation, certification, and oversight in the aviation sector. Once again, Deep Blue’s experts have worked alongside ENAV to identify the best tools for monitoring ATC fatigue in scientific literature. Through this comprehensive analysis, a new protocol has been defined, and a cutting-edge tool for real-time assessment of fatigue in the field has been developed. The tool takes into account the most influential factors contributing to fatigue risk, including:

  1. Workload;
  2. Level of underload or perceived boredom;
  3. Key sleep parameters (quality, duration, etc.);
  4. Level of vigilance, which provides an objective value of fatigue at the end of the work shift.

The Fatigue Monitoring Tool developed by Deep Blue and validated by ENAV has been implemented at five different locations so far (Rome ACC, FCO TWR, Padua ACC, Naples, and Parma). It accompanies air traffic controllers throughout their typical workday and collects fatigue-related data anonymously and non-invasively, before and after their shifts.

After a comprehensive analysis of the integrated data, we have observed that the current shift system implemented by ENAV is highly effective, exhibiting homogeneity and well-balanced characteristics – explains Michela Terenzi – no critical situations of workload or extreme boredom have been identified. The monitoring results affirm the efficiency of the rostering parameters in place”.

Additionally, the protocol developed by Deep Blue has allowed ENAV to better understand how to structure a monitoring system that must quickly and effectively detect and analyse an increasing amount of data, in order to obtain concrete insights into the effectiveness of the shift system in addressing fatigue issues, as well as any need for modification and opportunities for improvement.



The Fatigue Monitoring Tool developed by Deep Blue is a software-as-a-service product for fatigue monitoring and verification of the parameters of air traffic controller shift scheduling. “We are developing a cross-platform tool that empowers ANSP safety managers to efficiently plan and manage fatigue monitoring practices, ensuring seamless data collection among ATCs while adhering to the implemented protocol”, explains Giuseppe Frau, Computer Scientist and expert in human-machine interaction, heading the Tech Area at Deep Blue.

This leap forward marks a significant advancement, as the Fatigue Monitoring Tool allows for simple and comprehensive data collection and analysis of various factors related to ATC fatigue. Ensuring punctuality in data collection is essential to ensure compliance to the methodology.

“The tool itself is a remarkable engineering achievement, based on the successful implementation and validation of our protocol with ENAV – continues Terenzi – ATC fatigue monitoring is an essential practice on a European scale, and the Fatigue Monitoring Tool, in compliance with EASA regulations, could be adopted widely across Europe by featuring specific customization options for organisations”.

Due to the need for constant and systematic fatigue monitoring (rather than every 6 months), a flexible and customizable tool is crucial. With Deep Blue’s tool, organisations can create tailored data collection campaigns, generating valuable and easily interpretable analytics and dashboards on fatigue levels, as well as on the analysis of its primary components.

In Europe, dedicated working groups at ECTL and EASA are already collaborating to develop new, updated, and shared guidelines with major European ANSPs. These directives will incorporate Deep Blue’s contribution to fatigue mitigation through optimising rostering parameters. In view of future implementation, the Fatigue Monitoring Tool will allow for monitoring its efficiency over time and identifying the necessary corrective actions to maintain high levels of safety and mitigate the risk of ATC fatigue.


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