CAA NZ PPL Human Factors flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hypoxic hypoxia

Reduced oxygen partial pressure reaching the lungs, as at altitude. Blood cannot carry enough oxygen to tissues. Treat by descending, using supplemental oxygen, and limiting time at altitude.

Hypaemic hypoxia

Oxygen delivery is impaired because the blood carries less oxygen than normal, for example anaemia or carbon monoxide poisoning. The lungs may be normal but tissue oxygen is low.

Stagnant hypoxia

Blood flow to tissues is reduced, so oxygen delivery falls despite normal blood oxygen content. Causes include G-loading, cold, and heart failure. Treat by restoring circulation and reducing G.

Histotoxic hypoxia

Cells cannot use the oxygen delivered to them. Alcohol and cyanide interfere with cellular respiration. Blood oxygen may be normal, but tissue function is impaired.

Time of useful consciousness

The period from loss of oxygen supply until performance degrades enough to prevent effective action. It falls from about 20-30 minutes at 18,000 ft to under 30 seconds above 40,000 ft.

Supplemental oxygen rules NZ

Above 10,000 ft pressure altitude, pilots need supplemental oxygen when flying more than 30 minutes at that level. Above 13,000 ft, oxygen is required continuously. Check current CAA NZ rules.

Hyperventilation

Rapid breathing lowers carbon dioxide in the blood, causing dizziness, tingling, and muscle spasm. It can mimic hypoxia. Treat by slowing breathing and, if in doubt, use oxygen and descend.

Carbon monoxide poisoning

CO binds haemoglobin far more strongly than oxygen, blocking oxygen transport. Symptoms include headache, nausea, and cherry-red skin. Treat with 100% oxygen and land as soon as possible.

Somatogyral illusion

After a sustained turn, a sudden recovery to straight flight can feel like a turn in the opposite direction. The pilot may re-enter the original turn. Trust the instruments, not sensations.

Somatogravic illusion

During acceleration, the otolith organs signal a backward tilt, which feels like a climb. The pilot may push the nose down. During deceleration, the opposite occurs. Trust the instruments.

Coriolis illusion

Moving the head during a sustained turn creates a tumbling sensation because the semicircular canals are stimulated in more than one plane. Avoid head movements during turns in IMC.

Leans illusion

A false sensation of banking after a gradual turn is entered and then corrected. The pilot feels straight-and-level flight is a turn and may lean or bank further. Trust the attitude indicator.

Decompression sickness

Nitrogen bubbles form in tissues after exposure to reduced pressure. Symptoms include joint pain, rash, and neurological signs. Avoid flying soon after diving; follow CAA NZ diving intervals.

Barotrauma

Pressure differences damage ears or sinuses when equalisation fails, usually on descent. Pain, hearing loss, or bleeding can result. Do not fly with a cold or blocked Eustachian tube.

Eustachian tube equalisation

The tube connects the middle ear to the throat and must open to equalise pressure. Swallowing, yawning, or the Valsalva manoeuvre helps. Blockage causes ear pain on descent.

Night vision and vitamin A

Rod cells in the retina provide dim-light vision and need vitamin A. Dark adaptation takes about 30 minutes. Avoid bright light before night flight to preserve rod sensitivity.

Empty field myopia

In featureless conditions such as cloud or haze, the eyes focus at about 1 metre, making distant aircraft hard to see. Scan in sectors and blink to reset focus.

Visual scanning technique

Use short, regular eye movements across sectors rather than staring. The fovea sees detail only in a narrow cone, so scan to detect traffic. Pause briefly at each sector.

Circadian rhythm

The body's internal clock controls alertness, temperature, and sleep over about 24 hours. Disruption from shift work or crossing time zones causes fatigue. Plan rest before flying.

Fatigue effects on pilots

Fatigue slows reaction time, impairs judgement, and increases error rates. It cannot be overcome by willpower. Rest and proper sleep are the only reliable remedies.

Sleep debt

Accumulated loss of sleep reduces alertness and performance. It cannot be fully repaid in one night. Maintain regular sleep and avoid flying when significantly sleep-deprived.

Alcohol and flying

Alcohol impairs judgement, coordination, and vision, and effects persist after blood levels fall. NZ rules require no alcohol above the limit and no flying while impaired. Allow generous time.

Medication and flying

Many medicines, including antihistamines and sedatives, impair performance. Do not fly while taking them unless approved. Consult a CAA NZ aviation medical examiner before flying on new medication.

Hypoglycaemia

Low blood sugar causes confusion, sweating, and weakness. Eat regular meals and carry snacks on long flights. Treat with fast-acting carbohydrate and do not continue flying if symptoms persist.

Dehydration in flight

Dry cabin air and altitude increase fluid loss, causing fatigue and reduced alertness. Drink water regularly on long flights and avoid excess caffeine or alcohol.

Stress and performance

Moderate stress can improve focus, but excessive stress narrows attention and increases errors. Use checklists, prioritise tasks, and manage workload to keep stress manageable.

Situational awareness

Awareness of what is happening around the aircraft and what may happen next. It is lost through distraction, fixation, and fatigue. Regular instrument scans and verbal callouts help maintain it.

Task fixation

Focusing on one problem while ignoring other tasks or warnings. It reduces situational awareness and can lead to unsafe states. Use prioritisation and cross-check with other crew or instruments.

Crew resource management

Use of all available resources, including crew, equipment, and information, to achieve safe flight. It covers communication, leadership, and decision-making. Applies to single-pilot operations too.

Decision-making models

Structured models such as DECIDE help pilots assess options under pressure. Identify the problem, evaluate options, and act, then review. They reduce impulsive choices.

Hazardous attitudes

Attitudes such as impulsivity, invulnerability, and macho can lead to unsafe decisions. Recognise them and apply antidotes such as 'not so fast' or 'it could happen to me'.

Aircraft pressurisation failure

Loss of cabin pressure causes hypoxia and cold. Don oxygen masks immediately, descend to below 10,000 ft, and land as soon as practicable. Do not delay oxygen use.