CTO Fatigue Management & Human Factors 2 — Questions and Answers
Question 1: Which circadian rhythm phase is most dangerous for ATC performance errors?
- 0200–0600 local time (Correct answer)
- 0800–1200 local time
- 1400–1600 local time
- 1800–2200 local time
Correct answer: 0200–0600 local time
The 0200–0600 window aligns with the circadian nadir when alertness and cognitive performance are at their lowest.
Question 2: A controller notices a colleague making repetitive, minor readback corrections and appearing glassy-eyed. The BEST immediate action is to:
- Notify a supervisor and suggest the colleague take a break (Correct answer)
- Continue monitoring without interrupting workflow
- Ask the colleague to verify their medical certificate
- Increase the colleague's sector traffic to keep them engaged
Correct answer: Notify a supervisor and suggest the colleague take a break
Signs of impaired alertness should be reported to a supervisor so the controller can be relieved before a safety event occurs.
Question 3: Under FAA Order 7110.65, what is the minimum rest period required between ATC shifts?
- 9 hours
- 8 hours
- 10 hours (Correct answer)
- 12 hours
Correct answer: 10 hours
FAA policy requires a minimum of 10 hours off between shifts to allow adequate sleep and recovery.
Question 4: The concept of 'sleep inertia' is most relevant to ATC operations because it:
- Causes grogginess and impaired judgment immediately after waking (Correct answer)
- Refers to resistance to changing shift schedules
- Describes difficulty falling asleep before a night shift
- Indicates long-term insomnia caused by irregular schedules
Correct answer: Causes grogginess and impaired judgment immediately after waking
Sleep inertia is the transient state of reduced alertness and cognitive impairment that occurs right after waking, posing risk if a controller returns to position too quickly.
Question 5: Which scheduling practice best supports alertness for controllers rotating through night shifts?
- Forward-rotating schedules (day→evening→night) (Correct answer)
- Backward-rotating schedules (night→evening→day)
- Fixed permanent night schedules only
- Random assignment to minimize preference bias
Correct answer: Forward-rotating schedules (day→evening→night)
Forward rotation aligns with the natural tendency of the circadian clock to delay, making adaptation easier and reducing cumulative fatigue.
Question 6: A controller working a 10-hour shift reports feeling fine but has had only 5 hours of sleep for the past three nights. This is an example of:
- Cumulative sleep debt with impaired self-assessment (Correct answer)
- Acute fatigue with accurate self-assessment
- Circadian misalignment only
- Complacency with no fatigue component
Correct answer: Cumulative sleep debt with impaired self-assessment
Cumulative sleep debt degrades the ability to accurately self-assess fatigue, creating a hidden safety hazard.
Question 7: Which human factors model describes the interaction of Software, Hardware, Environment, and Liveware in ATC systems?
- SHELL model (Correct answer)
- HFACS model
- Swiss Cheese model
- Threat and Error Management model
Correct answer: SHELL model
The SHELL model (Hawkins/Reason) places the central Liveware (human operator) at the intersection of Software, Hardware, Environment, and other Liveware.
CTO Fatigue Management & Human Factors 2
Which circadian rhythm phase is most dangerous for ATC performance errors?