Human Performance and Limitations
What the exam tests
Human performance tests hypoxia, hyperventilation, decompression, spatial disorientation, visual and auditory illusions, fatigue, stress, workload, decision-making and crew resource management. Questions often ask for the first correct action, not the diagnosis.
Core threats
- Hypoxia causes euphoria, poor judgement and blurred vision; at high cabin altitude, use oxygen immediately and descend.
- Hyperventilation causes dizziness and tingling; it can mimic hypoxia. Confirm oxygen use and control breathing.
- Rapid decompression requires oxygen masks, emergency descent and communication with ATC.
- Somatogravic illusion during acceleration can feel like a nose-up attitude; rely on instruments.
- Fatigue reduces vigilance and slows reaction; controlled rest and careful rostering help but do not replace sleep.
- CRM requires clear briefings, assertiveness and closed-loop communication.
Worked example
After a night takeoff, the aircraft accelerates and the pilot feels a strong nose-up sensation. The attitude indicator shows a normal climb. This is somatogravic illusion caused by linear acceleration. The correct action is to cross-check the attitude indicator and altimeter, maintain the instrument climb, and not push forward. Trusting the sensation could cause a dangerous descent.
Traps
Do not assume a pilot who is hypoxic will recognise it; euphoria impairs self-check. Do not treat hyperventilation with more rapid breathing. Do not let a senior pilot's authority stop a junior crew member from speaking up. Do not use caffeine or stimulants as a substitute for rest.