Instrument Flight: Human Performance and Limitations
What the exam tests
Human Performance and Limitations looks at how pilots perceive, decide and perform under IFR workload: hypoxia, spatial disorientation, fatigue, stress, vision, hearing, CRM and automation. Questions often ask for the first corrective action.
Core rules
- Hypoxia: recognise euphoria, cyanosis and impaired judgement; use oxygen, descend and land.
- Spatial disorientation: trust instruments, not sensations; transfer to the instrument scan and use the autopilot if needed.
- Somatogravic illusion: acceleration feels like a climb; on go-around, resist pitching down.
- Fatigue and circadian rhythm degrade performance; controlled rest and proper rostering help.
- CRM: brief, assign roles, call 'go-around' and speak up; authority gradient matters.
- Automation: monitor mode annunciations and know what the aircraft is doing and why.
Worked example
At night after a long duty, a pilot accelerates for go-around and feels the aircraft pitching up. The correct response is to hold the instrument attitude and let the flight director command climb. Pitching down to 'correct' the illusion risks terrain contact.
Traps
- 'I feel fine' is not evidence of fitness.
- Hyperventilation can mimic hypoxia; both need oxygen or descent and assessment.
- Fatigue is not cured by coffee.
- Do not let the autopilot hide an abnormal flight path.