CAA NZ CPL Human Factors cheat sheet

Hypoxia types: hypoxic (low alveolar O2, e.g. altitude), hypemic (reduced O2-carrying capacity, e.g. anaemia, CO), stagnant (poor circulation), histotoxic (cells cannot use O2, e.g. alcohol, cyanide).

Time of useful consciousness at 25,000 ft is roughly 3–5 minutes; at 35,000 ft roughly 30–60 seconds; at 40,000 ft roughly 15–20 seconds. Above 10,000 ft NZ CPL aircraft normally require supplemental oxygen for flight crew when cabin altitude exceeds 10,000 ft (check aircraft/operator rules).

Hyperventilation vs hypoxia: hyperventilation causes dizziness, tingling, carpopedal spasm, and improves with slower breathing/rebreathing; hypoxia causes cyanosis, impaired judgement, and does not improve with rebreathing. When in doubt treat as hypoxia: don oxygen, descend.

Spatial disorientation: somatogravic illusion (linear acceleration mistaken for pitch-up), somatogyral illusion/leans (post-rotation), Coriolis illusion (head movement in turn). Recovery: believe instruments, not sensations; maintain instrument scan.

Night vision: rods are scotopic, low acuity, slow dark adaptation (20–30 min), poor at high illumination; cones are photopic, colour and acuity. Use off-centre viewing (10–15 degrees) to place image on rod-rich retina; avoid white light, use red lighting.

Decompression sickness (DCS): nitrogen bubbles form on decompression; symptoms include joint pain (bends), respiratory (chokes), neurological. Treatment: 100% oxygen, descend to lowest safe altitude, land and seek hyperbaric treatment.

Ear/sinus barotrauma: during descent, equalise via Valsalva, Toynbee, or yawning; if congested (cold/flu), do not fly. Barotrauma risk highest on descent due to pressure increase.

Carbon monoxide: colourless, odourless; binds haemoglobin ~200–250 times more avidly than oxygen, causing hypemic hypoxia. Suspect with heater use; symptoms: headache, nausea, confusion. Treatment: 100% oxygen, land.

Human error types: slips (correct intention, wrong execution), lapses (forgotten action), mistakes (wrong intention/plan), violations (deliberate deviation).

SHELL model: Software, Hardware, Environment, Liveware (centre). Liveware-liveware interfaces (crew, ATC) are most error-prone.

Swiss cheese model: latent conditions and active failures align, allowing an accident trajectory. Defences include checklists, SOPs, and cross-checking.

Threat and Error Management (TEM): identify threats, manage errors, avoid undesired aircraft states. Countermeasures: brief, monitor, cross-check, prioritise.

Fatigue: circadian low 0200–0600 and 1400–1600; effects include slowed reaction, poor vigilance, microsleeps. Mitigation: rest, controlled napping, caffeine, limit duty.

Stress: performance peaks at moderate arousal (Yerkes-Dodson curve); high stress causes narrowing of attention and fixation. Use breathing, prioritise, and delegate.

Situational awareness: perception, comprehension, projection. Loss leads to fixation, ambiguity, and expectation bias; counter with active monitoring and cross-checks.

Crew resource management (CRM): communication, leadership, teamwork, decision-making, workload management. Assertiveness and graded assertiveness (e.g. PACE: Probe, Alert, Challenge, Emergency) are core skills.

Decision-making models: DECIDE (Detect, Estimate, Choose, Identify, Do, Evaluate); FOR-DEC (Facts, Options, Risks, Decide, Execute, Check); use structured models under pressure.

Aeronautical decision-making: assess hazards using PAVE (Pilot, Aircraft, enVironment, External pressures) and IMSAFE (Illness, Medication, Stress, Alcohol, Fatigue, Emotion/Eating).

Risk assessment: use a risk matrix (likelihood x severity); identify, assess, mitigate, and review. Accept residual risk only when justified.

Judgement traps: plan continuation bias, sunk-cost, get-home-itis, peer pressure, and confirmation bias. Counter with early go/no-go decisions and an alternate plan.

Communication: use standard phraseology, readback, and closed-loop communication (sender confirms receiver understood). Avoid assumptions in ambiguous transmissions.

Workload management: prioritise aviate, navigate, communicate; shed non-essential tasks; use automation appropriately; monitor automation mode awareness.

Threats: weather, terrain, traffic, aircraft state, and personal pressures. Brief threats before flight; update with changing conditions.

Crew coordination: clear roles, shared mental model, briefings, and debriefs. Challenge errors constructively and support the captain/pilot flying.

Medical certification: NZ CPL requires a Class 1 medical; validity depends on age and privileges. Report any change in medical condition or medication to CAA.

Vision: standard requires distant visual acuity (corrected) and colour vision suitable for the privileges. Age-related presbyopia and night vision changes affect performance.

Hearing: ability to hear normal speech in cockpit noise; hearing loss typically at high frequencies first. Use headsets and protect hearing.

Medications: many impair performance (antihistamines, sedatives, some antibiotics). Do not fly while impaired; check with an aviation medical examiner (AME).

Alcohol: NZ CPL rule - no flying within 8 hours of consuming alcohol and blood alcohol must be below 20 mg/100 mL (0.02%). Some operators impose stricter limits.

Smoking/CO: smoking raises carboxyhaemoglobin, reduces altitude tolerance, and worsens night vision. Effects persist for hours.

Dehydration and nutrition: dehydration impairs cognition; caffeine and sugar spikes can affect alertness. Maintain hydration and regular meals.

Self-medication and drugs: illicit drugs and cannabis impair judgement and are prohibited. Prescription drugs require AME review before flight.

Perception: visual illusions include black hole approach (runway over water/dark), runway width illusion, and sloping terrain illusion; use instruments and approach aids.

Attention: limited capacity; vigilance decrement over time. Automation and fatigue reduce monitoring; use active scanning and callouts.

Memory: sensory, short-term (working, ~7 items), long-term. Checklists reduce reliance on memory; use written procedures for critical items.

Learning and habit: habit patterns (good and bad) form with repetition. Standard operating procedures build safe habits; bad habits are hard to break.

Motivation and personality: hazardous attitudes (anti-authority, impulsivity, invulnerability, macho, resignation) increase risk. Recognise and counter them.

Error management: detect, trap, and mitigate errors. Use cross-checks, readbacks, and sterile cockpit during critical phases.

Human information processing: sense, perceive, decide, act. Expectation bias can cause misreading of instruments; verify with multiple sources.

Stress and performance: acute stress narrows attention; chronic stress impairs sleep and judgement. Manage with rest, exercise, and support.

Fatigue risk management: identify signs (yawning, irritability, lapses), use rest breaks, controlled rest, and caffeine strategically; avoid flying when excessively fatigued.

Circadian rhythm: body clock entrained to light/dark; jet lag and shift work disrupt sleep. Eastward travel is usually harder than westward.

Sleep: adults need 7–9 hours; sleep debt accumulates. Naps of 20–30 minutes can improve alertness; longer naps risk grogginess (sleep inertia).

Workload: high workload causes errors; low workload causes boredom/vigilance decrement. Balance tasks and use automation to manage peaks.

Noise and vibration: noise increases fatigue and communication errors; vibration can blur vision and cause discomfort. Use headsets and reduce exposure.

Temperature and altitude: heat and cold impair performance; hypoxia above 10,000 ft (cabin) impairs judgement. Use oxygen and appropriate clothing.

Teamwork: shared mental model, clear communication, and mutual support reduce error. Debrief after flights to improve.

Safety culture: reporting errors (just culture) improves safety; blame culture reduces reporting. Encourage open communication and learning.