Correct: D)
Explanation: The correct answer is D because the proportion of oxygen in the atmosphere remains constant at approximately 21% regardless of altitude — what decreases with altitude is the total atmospheric pressure, and therefore the partial pressure of oxygen available for breathing. A, B, and C are all wrong because they suggest the percentage of oxygen itself changes with altitude, which is incorrect; the atmosphere maintains a homogeneous composition up to approximately 80 km.
Correct: C)
Explanation: The correct answer is C because smokers already have elevated carboxyhaemoglobin levels from carbon monoxide binding to their red blood cells, effectively reducing their oxygen-carrying capacity even before flight, so hypoxic symptoms manifest at lower altitudes compared to non-smokers. A is wrong because hypoxia is insidious — symptoms develop gradually and the pilot often does not recognise them. B is wrong because 4,000 ft is generally too low for noticeable hypoxic effects in most people. D is wrong because gasping for air is not a typical hypoxia symptom; instead, early signs include impaired judgment and reduced night vision.
Correct: C)
Explanation: The correct answer is C because carbon monoxide (CO) is a highly toxic gas produced by incomplete combustion of carbon-based fuels, and in aviation it can enter the cabin through leaking exhaust systems; it binds to haemoglobin with approximately 200 times the affinity of oxygen. A is wrong because cells produce carbon dioxide (CO2) as a metabolic waste product, not carbon monoxide. B is wrong because CO is odourless, colourless, and tasteless, making it extremely dangerous even at low concentrations. D is wrong because CO is a trace gas, not one of the major atmospheric components.
Correct: A)
Explanation: The correct answer is A because full dark adaptation requires approximately 30 minutes for the rod cells in the retina to reach maximum sensitivity through the regeneration of rhodopsin (visual purple), which is why pilots should avoid bright lights before night flying. B is wrong because one hour significantly overestimates the adaptation time. C is wrong because at 15 minutes the rods are only partially adapted and night vision is not yet at full capability. D is wrong because 5 minutes only allows for initial cone adaptation, not the complete rod-based dark adaptation needed for effective night vision.
Correct: B)
Explanation: The correct answer is B because hypotension (low blood pressure) can cause dizziness, lightheadedness, and even fainting, particularly when changing posture (orthostatic hypotension), which poses a flight safety risk. A is wrong because low blood pressure mainly causes symptoms during posture changes (standing up), not while lying down. C is wrong because elderly smokers are more commonly affected by high blood pressure (hypertension), not low blood pressure. D is wrong because low blood pressure can certainly cause symptoms that impair pilot performance.
Correct: A)
Explanation: The correct answer is A because at 20,000 ft without supplemental oxygen, the time of useful consciousness (TUC) is very short — typically only a few minutes — and rapid loss of consciousness follows due to severe hypoxia as the partial pressure of oxygen is far below what the body requires. B is wrong because pulmonary oedema develops over hours to days of high-altitude exposure, not during acute exposure. C is wrong because while shortness of breath may occur briefly, loss of consciousness is the most probable and dangerous outcome. D is wrong because fever is unrelated to altitude exposure.
Correct: A)
Explanation: The correct answer is A because during descent, external atmospheric pressure increases and trapped air within congested sinuses cannot equalise, creating a painful pressure differential — this is known as barosinusitis. B is wrong because while altitude changes in both directions can cause discomfort, descent is specifically the most problematic phase because the blocked sinuses cannot vent the increasing external pressure inward. C is wrong because during climb, expanding air within the sinuses can usually escape more easily, even through partially blocked passages. D is wrong because linear accelerations do not create the pressure differentials that cause sinus pain.
Correct: C)
Explanation: The correct answer is C because the classic symptoms of motion sickness (kinetosis) are dizziness, sweating, pallor, and nausea, which may progress to vomiting — all caused by a conflict between visual and vestibular sensory inputs. A is wrong because high fever is not a symptom of motion sickness; it indicates infection. B is wrong because neither high fever nor watery diarrhoea are associated with kinetosis. D is wrong because watery diarrhoea is a gastrointestinal symptom unrelated to vestibular-induced motion sickness.
Correct: C)
Explanation: The correct answer is C because a runway wider than the pilot is accustomed to makes the visual perspective appear as though the aircraft is lower and closer than it actually is, creating the impression of being at too low a speed and too low a height — the pilot may then tend to fly the approach too high. A is wrong because the wide runway creates the opposite illusion — feeling too low, not too high. B is wrong because the illusion relates to perceived height and proximity, not excessive speed. D is wrong because feeling too low in height would be a consequence, but the question asks about speed impression, and C correctly captures the speed-related illusion.
Correct: B)
Explanation: The correct answer is B because the eyes (specifically the retina) are the first organ to be affected by positive g-forces because retinal blood vessels are extremely sensitive to reduced blood pressure — the retina has the highest oxygen demand of any tissue, so when blood drains away under g-loading, vision degrades before consciousness is affected. A is wrong because the lungs continue to function under moderate g-forces. C is wrong because the brain loses function after the eyes — loss of consciousness (G-LOC) follows grey-out and blackout. D is wrong because muscles are not meaningfully affected by the blood pressure reduction that causes grey-out.
Correct: C)
Explanation: Effective visual scanning requires dividing the sky into sectors and pausing briefly on each one, allowing the eyes to focus and detect movement or contrast changes that indicate other aircraft. Option A and Option D advocate rapid, sweeping eye movements that prevent the eye from fixating long enough to register a small target. Option B similarly relies on continuous rolling motion, which reduces detection probability. Only Option C describes the proven sector-by-sector technique recommended in human factors training.
Correct: C)
Explanation: The human liver metabolises alcohol at a relatively constant rate of approximately 0.1 per mille per hour, regardless of the type of drink consumed or any attempted countermeasures such as coffee or exercise. Option A (0.5‰/h) and Option D (1‰/h) greatly overestimate the elimination rate, which could lead pilots to believe they are sober sooner than they actually are. Option B (0.3‰/h) is also too high. For SPL exam purposes, the standard value to remember is 0.1‰ per hour.
Correct: A)
Explanation: A sedentary lifestyle with insufficient physical activity is a well-established cardiovascular risk factor that increases the likelihood of heart attack. Option B (hypoglycaemia) is a metabolic condition primarily affecting energy supply to the brain, not a direct cardiac risk factor. Option C (undernutrition) and Option D (low cholesterol) are actually the opposite of known risk factors — it is overnutrition and high cholesterol that contribute to coronary artery disease. Regular exercise is one of the most effective protective measures against cardiovascular disease.
Correct: D)
Explanation: Amphetamines are strictly prohibited for pilots on duty because their adverse effects — including impaired judgment, overconfidence, risk-taking behaviour, and a crash of fatigue after the drug wears off — directly compromise flight safety. Option A and Option C suggest using amphetamines to combat fatigue during long flights, which is dangerous and illegal under aviation medical regulations. Option B implies that a co-pilot can mitigate the risk, but no crew arrangement makes stimulant use acceptable. The correct approach to fatigue is proper rest before flight, not pharmacological stimulation.
Correct: C)
Explanation: Risk area awareness refers to the pilot's conscious understanding that different phases of flight — takeoff, climb, cruise, descent, approach, and landing — each carry distinct hazards requiring specific vigilance. Option A is too narrow, focusing only on statistical accident rates rather than active awareness. Option B incorrectly interprets "risk area" as a physical location on the aerodrome. Option D describes risk area awareness as a procedure, but it is a mindset and competency, not a checklist or formal procedure. Effective risk area awareness allows the pilot to anticipate and mitigate threats proactively.
Correct: B)
Explanation: The DECIDE model follows the sequence: Detect, Estimate, Choose, Identify, Do, Evaluate. The first letter D stands for "Detect," meaning the pilot recognises that a change in the situation has occurred requiring a decision. Option A incorrectly assigns "Do" to the first D — "Do" is actually the fifth step, where the chosen course of action is implemented. Option C misplaces "Evaluate" as the first E, but the first E is "Estimate" (assess the significance of the change). Option D overstates the requirement — DECIDE is a helpful framework, not a mandatory procedure for every single decision.
Correct: A)
Explanation: Human factors research identifies five hazardous attitudes — anti-authority, macho, invulnerability, resignation, and impulsivity — and demonstrates that pilots can learn to recognise these tendencies in themselves and apply corrective antidotes. Option B incorrectly ranks hazardous attitudes; all five are dangerous and none should be dismissed as less threatening. Option C wrongly limits dangerous behaviour to inexperienced pilots, when in fact experienced pilots can also exhibit complacency and overconfidence. Option D denies the existence of hazardous attitudes entirely, contradicting decades of aviation safety research.
Correct: B)
Explanation: Selective attention is a cognitive phenomenon where concentrating intensely on one task causes the brain to filter out other stimuli, even obvious ones like a loud alarm. This is sometimes called "inattentional blindness" or "tunnel hearing." Option A confuses selective attention with a deliberate cockpit strategy, when it is actually an involuntary cognitive limitation. Option C describes instrument scan technique, not the psychological concept of selective attention. Option D incorrectly categorises it as a stress management method, when in fact selective attention under stress can be dangerous because critical warnings may go unnoticed.
Correct: A)
Explanation: The Yerkes-Dodson law demonstrates that moderate stress (eustress) enhances alertness, focus, and performance, while too little or too much stress degrades it — forming an inverted-U curve. Option B is incorrect because under-stimulation (boredom) is itself a form of stress that reduces vigilance and increases error rates. Option C oversimplifies by suggesting all cockpit stress is beneficial, when excessive stress causes cognitive overload and poor decision-making. Option D wrongly limits stress to brief overload, ignoring chronic stress from fatigue, personal problems, or sustained workload.
Correct: A)
Explanation: Research on circadian rhythms shows that the human endogenous biological clock runs on a cycle of approximately 25 hours when isolated from external time cues such as daylight and social schedules. Daily exposure to light resets (entrains) this internal clock to the 24-hour day-night cycle. Option B (20 hours) and Option D (30 hours) are incorrect values. Option C is wrong because the internal clock does not naturally run at exactly 24 hours — it requires daily resynchronisation by environmental cues called Zeitgebers.
Correct: C)
Explanation: Breathing fresh, cool air helps stabilise the autonomic nervous system and is one of the most effective immediate remedies for the onset of motion sickness. Option A (moving the head regularly) worsens symptoms by increasing conflicting vestibular stimulation. Option B (looking through the windows) can aggravate the sensory mismatch between visual and vestibular inputs in some individuals. Option D (drinking coffee) is a stimulant that can increase nausea and does not address the underlying vestibular conflict causing motion sickness.
Correct: C)
Explanation: A pilot accustomed to narrow runways perceives a wide runway as being closer (lower) than it actually is because the wider visual angle tricks the brain into interpreting the scene as a nearer surface. This creates the dangerous illusion of being too low, which may cause the pilot to fly a higher approach than necessary and flare too high. Option A and Option D describe slope-related illusions unrelated to runway width. Option B describes the opposite illusion — the pilot feels lower, not higher. Understanding this visual trap is essential for safe approaches to unfamiliar aerodromes.
Correct: B)
Explanation: Middle ear pressure equalisation problems are most likely during rapid descent because the Eustachian tube must open to allow higher-pressure air from the throat into the middle ear cavity, which is physiologically more difficult than the reverse. During ascent, expanding air in the middle ear vents outward relatively easily. Option A (long high-altitude flight) maintains a constant cabin altitude and does not create pressure differentials. Option C (long climb) involves gradual pressure decrease that the ear handles well. Option D (negative g-forces) affects the vestibular system, not middle ear pressure.
Correct: D)
Explanation: The composition of the atmosphere remains constant at approximately 21% oxygen and 78% nitrogen from sea level up to about 80 km altitude. What decreases with altitude is not the percentage of oxygen but the total atmospheric pressure, and therefore the partial pressure of oxygen available to the lungs. Option A and Option B incorrectly suggest that the proportion changes. Option C proposes an increase, which is also wrong. The key concept for pilots is that hypoxia at altitude results from reduced partial pressure, not from a change in oxygen percentage.
Correct: A)
Explanation: Carbon monoxide (CO) binds to haemoglobin approximately 200 times more readily than oxygen, forming carboxyhaemoglobin and drastically reducing the blood's oxygen-carrying capacity. Even very low concentrations can cause headaches, impaired judgment, and eventually total incapacitation or death. Option B and Option D dangerously dismiss CO as harmless — it is one of aviation's most insidious threats because it is colourless and odourless. Option C incorrectly suggests that only prolonged exposure is harmful, when in fact even brief exposure to moderate concentrations can be lethal.
