Human Performance and Limitations
Human Performance and Limitations
This domain tests how pilot physiology, psychology and decision-making affect flight safety. Expect hypoxia, hyperventilation, spatial disorientation, fatigue, stress, vision, hearing, information processing and crew resource management.
Core rules
- Hypoxia reduces oxygen to the brain; early signs include euphoria, impaired judgement, tingling and visual changes. Correct action is supplemental oxygen and descent.
- Hyperventilation can mimic hypoxia; it causes dizziness and tingling but is treated by controlled breathing, reassurance and, if doubt exists, oxygen.
- Spatial disorientation occurs when vestibular illusions conflict with instruments. Trust the instruments and use a stabilised scan.
- Fatigue and stress degrade attention and decision-making. Use personal limits, rest and simple prioritisation.
- Vision at night is poor in the central field; use off-centre viewing. Hearing protection prevents cumulative loss.
Worked example
At 12,000 ft cabin altitude without oxygen, a pilot develops tingling, dizziness and narrowed vision. Hyperventilation can produce similar symptoms, but the altitude makes hypoxia the priority. The correct response is 100% oxygen and descent, not simply breathing faster. The reasoning is that hypoxia is time-critical and reversible with oxygen.
Traps
Do not assume hyperventilation is always the cause; at altitude, treat for hypoxia first. Do not rely on feelings in cloud; vestibular illusions persist. Do not ignore fatigue as a 'personal weakness'; it is a performance limitation.