CAA NZ CPL Human Factors key terms

A condition in which the body's tissues receive insufficient oxygen. In aviation it commonly results from high altitude, cabin depressurisation, or impaired oxygen delivery, causing judgement loss, euphoria, and eventual unconsciousness.

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

The period between loss of adequate oxygen supply and the point at which a person can no longer take protective action. It shortens rapidly with increasing altitude and is reduced by exertion or cold.

An unplanned loss of cabin pressure at altitude. Crew must don oxygen masks promptly, initiate an emergency descent, and manage communication, because hypoxia and cold can quickly degrade performance.

Breathing faster or deeper than metabolic needs, lowering blood carbon dioxide. Symptoms resemble hypoxia, including dizziness, tingling, and anxiety; treatment is controlled slower breathing or, if hypoxia is possible, oxygen.

Injury or pain to gas-filled body cavities caused by pressure changes, most often the ears and sinuses during climb or descent. It is managed by equalising pressure and avoiding flight when congested.

Illness caused by dissolved nitrogen forming bubbles in tissues when ambient pressure falls rapidly, as in high-altitude flight. Symptoms include joint pain, skin mottling, and neurological effects; treatment is descent and medical care.

Failure to correctly perceive aircraft attitude or motion relative to the earth. It arises when visual cues are poor and vestibular illusions dominate, and is countered by trusting instruments and avoiding sudden head movements.

A false sensation of pitch caused by linear acceleration or deceleration, such as feeling a nose-up attitude during take-off acceleration. Pilots must ignore it and rely on flight instruments.

The inner-ear sense organs, including semicircular canals and otoliths, that detect rotation and linear acceleration. They cannot distinguish gravity from acceleration in sustained conditions, producing many spatial illusions.

The body's sense of touch, pressure, and position from skin, muscles, and joints. It contributes to seat-of-the-pants attitude perception but is unreliable in coordinated flight and can reinforce spatial disorientation.

Visual misperceptions of height and distance on approach caused by runway slope, width, terrain, or lighting. They can lead to undershooting or overshooting; pilots should use instrument guidance and standard glidepath cues.

A night visual illusion where a runway without surrounding ground lighting appears closer and higher than it is, encouraging a low approach. Instrument reference and a stabilised approach mitigate the risk.

Misleading perceptions arising from the eyes, inner ear, or body senses in flight, such as false horizons or vection. Recognising their causes and prioritising instrument indications reduces their danger.

An illusion in which a single stationary light in a dark featureless sky appears to move. It can mislead pilots during night formation or station-keeping and is reduced by visual reference and instrument cross-checks.

The eye's ability to see in dim light, mainly through rod cells and the chemical rhodopsin. It is degraded by bright light, smoking, hypoxia, and fatigue, and requires dark adaptation of about 20 to 30 minutes.

A physiological state of reduced mental or physical performance capability resulting from sleep loss, extended wakefulness, circadian disruption, or workload. It impairs attention and decision-making and is managed through rest and duty limits.

The body's internal roughly 24-hour cycle governing sleep, alertness, and temperature. Disruption by shift work or time-zone travel causes jet lag and reduced performance at biologically low points.

Temporary reduced alertness and impaired performance immediately after waking, especially from deep sleep or at the wrong circadian phase. It can affect pilots who nap in flight or wake for early duty.

The body's response to demands or threats, which can be useful at moderate levels but harmful when excessive or prolonged. It narrows attention and impairs judgement, and is managed through training, planning, and support.

The cognitive process of assessing a situation and choosing a course of action. In aviation it combines knowledge, experience, and risk assessment, and can be degraded by fatigue, stress, and hazardous attitudes.

Five counterproductive mindsets identified in aviation safety training: anti-authority, impulsivity, invulnerability, macho, and resignation. Each has an antidote, such as following rules or slowing down, to restore sound judgement.

An accurate ongoing perception and understanding of what is happening around the aircraft and what may happen next. Loss of it precedes many accidents and is maintained by active scanning and cross-checking.

The mental and physical effort required to perform tasks. Excessive workload causes errors and task shedding, while very low workload can reduce vigilance; both are managed through prioritisation and automation use.

The process of selecting between alternatives under uncertainty and time pressure. Good aeronautical decision making uses structured models, considers consequences, and reviews outcomes to improve future choices.

The exchange of information between crew, air traffic services, and others. Clear standard phraseology and closed-loop readback reduce misunderstanding, which remains a common factor in incidents.

Training and practices that use all available resources, including crew, equipment, and information, to achieve safe flight. It emphasises communication, leadership, teamwork, and workload management.

The willingness to state concerns clearly and respectfully, and to question a course of action when safety is in doubt. It balances authority gradient and supports effective crew coordination.

The perceived difference in power or expertise between crew members, which can inhibit junior members from speaking up. Steep gradients increase error; briefings and invitation to challenge reduce the effect.

A rule prohibiting non-essential conversation and activity during critical phases of flight such as taxi, take-off, approach, and landing, to protect attention and communication.

An action or inaction that deviates from intention or expectation. Errors are classified as slips, lapses, mistakes, or violations, and understanding them supports better design and training.

A deliberate deviation from rules or procedures. It may be routine or exceptional, and is addressed through culture, supervision, and understanding of the reasons behind the rules.

A framework in which crews anticipate threats, trap errors before they affect the flight, and manage any resulting undesired aircraft state. It links human performance to operational safety.

The study of how people interact with equipment, procedures, and environments, aiming to optimise performance and safety. It covers perception, cognition, physiology, teamwork, and system design.

Pain or injury in the facial sinuses caused by blocked pressure equalisation during climb or descent, often with a cold. It is prevented by avoiding flight when congested and treated by stopping the pressure change.

Perceptual misinterpretations of real sensory input, common in aviation when visual or vestibular cues conflict with actual aircraft state. Training and instrument reliance are the primary defences.