Human Performance and Limitations
The human in the loop
This domain covers the senses used in flight, the limitations of vision and hearing, spatial disorientation, hypoxia, hyperventilation, decompression, fatigue, stress, workload, situational awareness, decision making, communication and crew resource management. Learn the difference between the vestibular and visual systems and why the vestibular system can mislead in cloud or at night. Understand the effects of altitude on oxygen saturation, the time of useful consciousness, and the signs of hypoxia. Also learn the principles of human error, the SHELL model and the error chain.
Traps in questions
A frequent trap is assuming that a pilot can "feel" the aircraft's attitude reliably - in fact, without visual reference, the vestibular system produces false sensations. Another is confusing hypoxia with hyperventilation, which can look similar but has different causes and responses. Questions also test fatigue as a cumulative factor, and the difference between an error and a violation.
Worked example
"A pilot in cloud feels a steep bank and corrects, but the aircraft is actually level. What is happening?" Answer: somatogravic or vestibular illusion; the correct response is to trust the instruments and cross-check. Rule of thumb: in IMC, believe the instruments, not your body.
Key points
- Without visual reference, the vestibular system can give false sensations.
- Hypoxia and hyperventilation differ in cause and response.
- Fatigue is cumulative and degrades decision making.
- Distinguish errors from violations.
- In IMC, trust the instruments.