Human Factors and Performance
Domain 6 tests how you use human-factors models to explain and prevent controller error, not how well you recite them. Expect questions on situational awareness, fatigue, workload, communication and team coordination.
Models you must apply
SHELL connects Software, Hardware, Environment and Liveware; the liveware-liveware interface is usually the most fragile. Reason's Swiss-cheese model shows latent conditions and active failures lining up. Threat and Error Management asks you to anticipate threats, trap errors and manage undesired states. ICAO Doc 9683 provides the human-factors training framework.
Performance limits
Fatigue degrades vigilance, reaction time and decision quality; circadian low, sleep debt and long duties matter. Hypoxia, noise, vibration, heat and glare affect performance. Situational awareness has three levels: perception, comprehension and projection; losing level 3 is the dangerous one.
Worked example: a controller issues FL280 to an aircraft while a flight strip at FL290 sits on the same bay. The strip belongs to a different flight. The controller sees what is expected, not what is there. The readback includes FL280; the crew queries it, and the clearance is corrected. In SHELL terms, the Software and Liveware interaction produced the error; the readback trapped it.
Traps: writing human error as the cause and stopping; blaming an individual without examining the system; confusing workload with stress; ignoring the value of readback and cross-check.