Air traffic controller fatigue is an even more widespread and serious issue than flight crew fatigue. ATCO working hours led to various cognitive performance degradations associated with sleep deprivation and working at times for which humans are not biologically programmed. However, when considering safety, the impacts of fatigue are less clear, as they are influenced by our own awareness of our state and by our ability to develop strategies to overcome the detrimental effects of fatigue. Therefore, the prevention of the negative safety outcomes linked to fatigue should make it possible to reduce the occurrence of fatigue with appropriate scheduling, but also by providing ATCOs with the means to detect and mitigate its effect.
Prior to 2015, air traffic controllers regularly worked the “Rattler” schedule, with five consecutive eight-hour shifts (with eight-hour breaks in between) and three-day weekends. NASA and the FAA studied its impact on performance, but refused to reveal the results of the study for four years. The Rattler was revealed to produce considerable fatigue among air traffic controllers, with many getting only 5.8 hours of sleep per day (3.1 on midnight shifts). Two in ten controllers made significant errors in the preceding year, and half attributed those errors to fatigue. Why NASA and the FAA withheld the information for so long is unknown.
Fatigue has been on the National Transportation Safety Board (NTSB) “Most Wanted List” since the initial list in 1990. Warning signs can include drowsiness, lack of communication, and requests for easier roles. Sleep is the best solution, even for night-shift employees; other measures merely act as stop-gaps.
- Increased frequency of Operational Errors: An occurrence attributable to an element of the air traffic control system in which:
- Less than the applicable separation minima results between two or more aircraft, or between an aircraft and terrain or obstacles; or
- An aircraft lands or departs on a runway closed to aircraft operations
- Impaired performance: delayed, erroneous or chaotic responses to normal stimuli
- Reduced ability for the controller to process complex information and cope with the unexpected. It is when the automation fails or evidences unexpected behavior that the human needs to step in. Fatigue dramatically compromises the ability of the flgith crew to perform as needed in off-nominal conditions.
- Automation mode confusion.
- Reduced alertness
- Adverse physiological consequences: stressors affecting alertness
- Adverse effects of long commutes on performance
- Reversions to “fight-or-flight,” panic or freeze instinctive self-preservation behaviors in emergency situations; reflexive response to stimulation
- Failure to report errors and omissions arising from fatigue that do not necessarily result in reportable incidents
- Poor environmental characteristics of rest areas in air traffic control facilities
- A recent FAA Office of Inspector General report found that pilots might not be reporting all instances of fatigue. The report noted that, of 33 air carrier pilots interviewed by OIG researchers, 26 (79 percent) said that, at some time, they had been fatigued while on duty; nevertheless, only eight pilots notified their air carrier of their condition. Among the reasons cited for not reporting fatigue was the fear of “punitive action from their employers.”