Human Factors - CAA NZ CPL
Human Factors is the CPL subject that asks why competent pilots still make mistakes, and what defences catch them. The NZ CAA syllabus tests physiology, psychology, human error, communication, decision-making and automation, always in the operational setting of a light single or twin.
Frameworks you must be able to apply
- SHELL model: Liveware sits at the centre; mismatches at the Software, Hardware, Environment and Liveware interfaces create error traps.
- Reason's model: active failures at the sharp end versus latent conditions at the organisational end. Defences are layers with holes; an accident needs the holes to line up.
- Threat and Error Management: threats are external, errors are pilot actions, and undesired aircraft states form the bridge to an accident. Countermeasures are to avoid, trap and mitigate.
Physiology that changes the flight
Hypoxia is insidious: euphoria and poor judgement appear before cyanosis. Time of useful consciousness is roughly 30–60 seconds at FL350 and 15–20 seconds at FL400. Hyperventilation causes dizziness and tingling - slow the breathing rate, but always exclude hypoxia first. Night or cloud invites spatial disorientation: the somatogravic illusion, the leans and the black-hole approach.
Worked example
A pilot conducts a night go-around in IMC. Acceleration produces a somatogravic illusion of pitch-up, so the pilot pushes forward and the aircraft descends. The error is perceptual, not careless. The correct response is to trust the instruments, establish attitude and performance, then re-engage.
Traps that cost marks
- Treating the “eight hours bottle-to-throttle” rule of thumb as the legal standard; NZ sets a blood alcohol limit of 20 mg/100 mL, and hangover and fatigue effects are separate.
- Confusing active failures with latent conditions.
- Offering “pilot error” as a cause instead of describing the mechanism.
- Assuming CRM is only about personality; it also covers briefings, monitoring and assertiveness.