CAA NZ PPL Human Factors key terms

A shortage of oxygen reaching the body tissues. In flight it impairs night vision first, then judgement, coordination and consciousness, often without the pilot noticing the deterioration.

Insufficient oxygen supply to the brain and other tissues. Effects worsen with altitude and are dangerous because the pilot's own judgement is affected before they recognise the problem.

Oxygen shortage caused by reduced oxygen partial pressure in the air breathed, as at altitude. It is the most common form in aviation and is corrected by descending or using supplemental oxygen.

The period between loss of adequate oxygen and inability to take corrective action. It shortens rapidly with altitude, from minutes at 25,000 feet to seconds above 40,000 feet.

The equivalent altitude pressure inside a pressurised aircraft cabin, normally around 6,000 to 8,000 feet. A pressurisation failure raises cabin altitude and can produce hypoxia.

Rapid or deep breathing that removes too much carbon dioxide from the blood. Symptoms resemble hypoxia, including dizziness, tingling and confusion, and treatment is to slow the breathing rate.

Illness caused by breathing carbon monoxide, typically from engine exhaust or a faulty cabin heater. It causes headache, drowsiness and impaired judgement, and is hard to detect because the gas is odourless.

A pilot's mistaken perception of aircraft attitude or motion, usually when visual references are poor. The pilot may feel level while banked or climbing while descending, and must trust the instruments.

False sensations of motion arising from the inner ear's balance organs, especially during prolonged turns or rapid head movements. The pilot feels a turn continuing after it stops, or a false tumbling sensation.

A false sensation of pitch caused by acceleration or deceleration. During takeoff acceleration the pilot may feel the aircraft is climbing steeply and push forward, risking a low nose attitude.

Misleading perceptions of distance, height or slope caused by runway shape, terrain, lighting or weather. They can lead to a low or high approach, so the pilot should cross-check instruments.

An approach at night over dark ground with few visual cues, where the runway appears closer and higher than it is. The pilot tends to fly a low approach and should rely on instruments.

The sense of body position and pressure from skin, muscles and joints. It provides some seat-of-the-pants cues in flight but is unreliable in turbulence or uncoordinated flight.

A pilot's ongoing understanding of aircraft state, environment, and what is likely to happen next. Loss of it is a common precursor to errors and is rebuilt by scanning and verbalising.

The mental and physical effort required to manage tasks in flight. Excessive workload causes task shedding and error, while very low workload can lead to boredom and reduced vigilance.

The general level of alertness and mental activation. Performance is best at moderate arousal; too little causes inattention and too much causes stress and narrowed focus.

A state of tiredness that reduces alertness, slows reactions and impairs judgement. It accumulates with insufficient sleep and long duty periods and cannot be overcome by willpower.

The body's internal daily cycle that regulates sleep, alertness and temperature. Disruption by shift work or time-zone crossing causes fatigue and reduced performance at certain times.

The body's response to demands or threats, useful in small amounts but harmful when prolonged. Excessive stress narrows attention, increases errors and can lead to poor decisions.

Overconfidence or reduced vigilance arising from routine or uneventful conditions. It leads pilots to skip checks and accept deviations, so disciplined use of checklists counters it.

The process of choosing a course of action from available options. Good aeronautical decision making uses structured models, considers alternatives and is reviewed as conditions change.

Mindset patterns such as impulsivity, invulnerability, machismo, resignation and anti-authority that predispose pilots to risky decisions. Each has a recognised antidote used in decision training.

Training and practices that use all available resources, including crew, equipment and support, to improve safety. It emphasises communication, teamwork, briefing, monitoring and assertion.

The willingness to speak up clearly when something seems wrong, regardless of rank. It prevents errors being missed when a less experienced crew member spots a problem.

The clear exchange of information between crew, air traffic control and others. Standard phraseology, readback and closed-loop confirmation reduce misunderstanding and error.

Following written checklists consistently, including the challenge-and-response method, rather than relying on memory. It protects against omission under high workload or distraction.

Anything that draws attention away from the primary task of flying or monitoring. Interruptions during critical phases are a frequent cause of omissions and must be managed deliberately.

A sequence of linked mistakes and unsafe conditions that leads to an accident. Breaking any one link, for example by challenging a deviation, can prevent the outcome.

A framework in which crews anticipate threats, detect errors and respond before they cause harm. It treats error as normal and focuses on trapping it early.

An unintended action or omission by a person that leads to an undesired outcome. Most aviation accidents involve error, so systems and training are designed to tolerate it.

An approach that distinguishes honest mistakes from reckless or deliberate violations. It encourages reporting of errors without fear while still holding people accountable for gross negligence.

A structured set of processes for identifying hazards, assessing risk and improving safety performance. It includes reporting, investigation and continuous improvement across the organisation.

Judging the likelihood and severity of a hazard to decide whether and how to proceed. It should be done before flight and updated as conditions change.

Self-set limits on weather, fuel, visibility and other factors that a pilot will not exceed. They provide a buffer against pressure and are reviewed after each flight.

A fixation on reaching the destination that overrides sound judgement about weather, fuel or aircraft condition. It is a common hazardous attitude countered by planning alternatives in advance.

Loss of body water that reduces alertness, causes headache and impairs concentration. It is common in dry cabin air and worsens the effects of fatigue and hypoxia.

Continuous aircraft sound and shaking that cause fatigue and reduce hearing and concentration. Hearing protection and limiting exposure help maintain performance.

The use of central and peripheral vision for scanning and collision avoidance. At night, off-centre viewing is needed because the most sensitive retinal cells are away from the centre.