Human Performance and Limitations
Human Performance and Limitations tests physiology, psychology, sensory illusions, fatigue, stress, CRM and error management. The focus is recognition and effective countermeasures in two-crew operations.
Core rules
- Hypoxia: time of useful consciousness falls with altitude; at FL350 it is roughly 30 to 60 seconds after rapid decompression. Don oxygen first, then communicate.
- Hyperventilation can mimic hypoxia; control breathing and verify oxygen.
- Spatial disorientation: trust instruments, not sensations; avoid sudden head movements in IMC.
- Fatigue is cumulative; caffeine and breaks do not restore full performance.
- CRM uses briefings, callouts, cross-checks and assertiveness to trap errors.
- Alcohol, medication and stress degrade judgement; follow medical certification rules.
Worked example
After a rapid decompression at FL350, a pilot feels dizzy and euphoric. The correct sequence is: don the mask and establish oxygen, confirm pressurization, initiate the emergency descent as required, then assess crew and passengers. Trying to diagnose the feeling before oxygen delays the essential action.
Traps
- Treating euphoria as reassurance rather than hypoxia.
- Fixating on one task while the other pilot is saturated.
- Assuming a checklist replaces decision-making.
- Ignoring cumulative fatigue on the second consecutive early start.