Human Performance and Limitations
Human Performance and Limitations tests how pilots perceive, decide and act under workload, and how hypoxia, fatigue, disorientation and communication failures degrade safety.
Core concepts
- Hypoxia reduces oxygen to tissues; symptoms include euphoria, impaired judgement and blurred vision. Time of useful consciousness falls with altitude.
- Hyperventilation produces dizziness and tingling and can mimic hypoxia; treatment is controlled breathing and reassurance.
- Spatial disorientation includes somatogravic illusion during acceleration and the black-hole illusion on dark approaches.
- Fatigue and circadian disruption slow reaction time and increase error; CRM depends on briefings, assertiveness and closed-loop communication.
Worked example
On a dark night approach over water, a pilot sees few ground lights and pitches down because the runway appears higher than it is. This is the black-hole illusion. The correct response is to cross-check the PAPI, altimeter and VSI and fly the instrument approach rather than trust the false horizon.
Traps
- Assuming hypoxia always causes obvious breathlessness; euphoria can hide it.
- Treating hyperventilation as hypoxia and giving oxygen without reassessing.
- Ignoring the somatogravic illusion during a go-around or acceleration.
- Accepting a first officer’s concern as “not important” instead of resolving it.