# Human Performance --- ### Q31: A Grey-out is the result of... ^t40q31 - A) Hypoxia. - B) Positive g-forces. - C) Hyperventilation. - D) Tiredness. **Correct: B)** > **Explanation:** The correct answer is B because grey-out is caused by positive g-forces pulling blood away from the head toward the lower body. As retinal blood pressure drops, vision progressively fades -- first losing colour (grey-out), then vision entirely (blackout), and finally consciousness (G-LOC). A (hypoxia) causes different symptoms including cyanosis and impaired judgment. C (hyperventilation) causes tingling and spasms. D (tiredness) reduces alertness but does not cause the specific visual loss pattern of grey-out. ### Q32: Visual illusions are mostly caused by... ^t40q32 - A) Colour blindness. - B) Misinterpretation of the brain. - C) Rapid eye movements. - D) Binocular vision. **Correct: B)** > **Explanation:** The correct answer is B because the brain actively constructs perception based on expectations, patterns, and assumptions rather than passively recording reality. When environmental cues are ambiguous or unusual (common in aviation -- unfamiliar terrain, reduced visibility, featureless sky), the brain fills gaps with incorrect "best guesses." A (colour blindness) is a specific visual deficiency, not a general cause of illusions. C (rapid eye movements) is a normal visual function. D (binocular vision) provides depth perception and actually reduces illusion susceptibility. ### Q33: The average decrease of blood alcohol level for an adult in one hour is approximately... ^t40q33 - A) 0.1 percent. - B) 0.3 percent. - C) 0.03 percent. - D) 0.01 percent. **Correct: D)** > **Explanation:** The correct answer is D because the liver metabolises alcohol at approximately 0.01% (0.1 g/L) blood alcohol concentration per hour, largely independent of body weight. This means significant impairment can persist well into the following day after heavy drinking. A (0.1%) would clear alcohol ten times faster than reality. B (0.3%) is unrealistically fast. C (0.03%) is three times the actual rate. The EASA "8-hour bottle to throttle" rule is a minimum, not a guarantee of sobriety. ### Q34: Which answer states a risk factor for diabetes? ^t40q34 - A) Sleep deficiency - B) Overweight - C) Smoking - D) Alcohol consumption **Correct: B)** > **Explanation:** The correct answer is B because overweight and obesity are the primary modifiable risk factors for type 2 diabetes, as excess adipose tissue causes insulin resistance. In aviation medicine, diabetes is a significant concern because hypoglycaemic episodes can impair consciousness and cognitive function. A (sleep deficiency), C (smoking), and D (alcohol) carry various health risks but are not the primary established risk factor for diabetes onset. ### Q35: A risk factor for decompression sickness is... ^t40q35 - A) Sports. - B) 100 % oxygen after decompression. - C) Scuba diving prior to flight. - D) Smoking. **Correct: C)** > **Explanation:** The correct answer is C because scuba diving dissolves nitrogen into body tissues under elevated ambient pressure. If the diver flies before sufficient off-gassing time (typically 12-24 hours depending on dive profile), the reduced cabin pressure causes nitrogen to form bubbles -- decompression sickness. A (sports) does not dissolve excess nitrogen. B (100% oxygen) actually accelerates nitrogen elimination and is a treatment, not a risk factor. D (smoking) impairs oxygen transport but is not a decompression sickness risk factor. ### Q36: Which statement is correct with regard to the short-term memory? ^t40q36 - A) It can store 10 (+/-5) items for 30 to 60 seconds - B) It can store 5 (+/-2) items for 1 to 2 minutes - C) It can store 7 (+/-2) items for 10 to 20 seconds - D) It can store 3 (+/-1) items for 5 to 10 seconds **Correct: C)** > **Explanation:** The correct answer is C because George Miller's classic 1956 research established that short-term (working) memory holds 7 plus or minus 2 chunks of information, retained for approximately 10-20 seconds without rehearsal. In aviation, this is critically important: ATC clearances, frequencies, and altitudes must be written down immediately because they fade within seconds if not actively rehearsed. A overestimates both capacity and duration. B and D underestimate capacity or misstate duration. ### Q37: For what approximate time period can the short-time memory store information? ^t40q37 - A) 35 to 50 seconds - B) 3 to 7 seconds - C) 10 to 20 seconds - D) 30 to 40 seconds **Correct: C)** > **Explanation:** The correct answer is C because without active rehearsal, items in short-term memory fade within approximately 10-20 seconds. This is why read-back procedures in radio communication are essential -- they force the pilot to actively process and repeat information, moving it from passive storage into a more durable encoded state. A and D overestimate retention time. B underestimates it. Understanding this limitation helps pilots develop habits like immediately writing down frequencies and clearances. ### Q38: What is a latent error? ^t40q38 - A) An error which has an immediate effect on the controls - B) An error which only has consequences after landing - C) An error which is made by the pilot actively and consciously - D) An error which stays undetected in the system for a long time **Correct: D)** > **Explanation:** The correct answer is D because latent errors (latent conditions) in James Reason's error model are failures embedded in the system -- poor design, inadequate procedures, organisational pressures, or maintenance shortcuts -- that remain dormant and undetected until they combine with an active error to cause an accident. A describes an active error with immediate consequences. B is too narrow -- latent errors can have consequences at any time. C describes an intentional violation, not a latent system failure. ### Q39: The ongoing process to monitor the current flight situation is called... ^t40q39 - A) Constant flight check. - B) Situational thinking. - C) Situational awareness. - D) Anticipatory check procedure. **Correct: C)** > **Explanation:** The correct answer is C because situational awareness (SA), as defined by Mica Endsley, is the continuous process of perceiving elements in the environment, comprehending their meaning, and projecting their future status. Loss of SA is a primary contributing factor in controlled flight into terrain, mid-air collisions, and spatial disorientation accidents. A, B, and D are not established aviation safety terminology and do not capture the three-level perception-comprehension-projection model that defines SA. ### Q40: Regarding the communication model, how can the use of the same code during radio communication be ensured? ^t40q40 - A) By the use of proper headsets - B) By the use of radio phraseology - C) By using radios certified for aviation use only - D) By a particular frequency allocation **Correct: B)** > **Explanation:** The correct answer is B because standardised ICAO radio telephony phraseology ensures both sender and receiver use identical, unambiguous terminology with pre-agreed meanings, minimising misunderstanding risk. In communication theory, this means sharing the same codebook. A (headsets) improve audio quality but not code consistency. C (certified radios) ensure transmission quality, not message clarity. D (frequency allocation) organises traffic separation, not message encoding. ### Q41: In what different ways can a risk be handled appropriately? ^t40q41 - A) Avoid, reduce, transfer, accept - B) Avoid, ignore, palliate, reduce - C) Ignore, accept, transfer, extrude - D) Extrude, avoid, palliate, transfer **Correct: A)** > **Explanation:** The correct answer is A because the four standard risk management strategies are: Avoid (eliminate the hazard entirely), Reduce (implement controls to lower probability or severity), Transfer (shift risk to another party, e.g. insurance), and Accept (consciously acknowledge residual risk within acceptable limits). B, C, and D all include "ignore," "palliate," or "extrude," which are not recognised risk management strategies. Ignoring a risk is never acceptable in aviation. ### Q42: Under which circumstances is it more likely to accept higher risks? ^t40q42 - A) During flight planning when excellent weather is forecast - B) During check flights due to a high level of nervousness - C) Due to group-dynamic effects - D) If there is not enough information available **Correct: C)** > **Explanation:** The correct answer is C because group dynamics produce "risky shift" -- groups tend to make bolder decisions than individuals acting alone. Social pressure, conformity, diffusion of responsibility, and deference to perceived authority all suppress individual risk awareness. This is a core CRM concept. A (excellent weather) would logically reduce risk. B (nervousness) tends to make people more cautious, not less. D (insufficient information) should prompt caution, though in practice it sometimes does not. ### Q43: Which dangerous attitudes are often combined? ^t40q43 - A) Self-abandonment and macho - B) Invulnerability and self-abandonment - C) Macho and invulnerability - D) Impulsivity and carefulness **Correct: C)** > **Explanation:** The correct answer is C because macho ("I can do it") and invulnerability ("It won't happen to me") frequently occur together, both stemming from overconfidence and underestimation of risk. A pilot who believes they are immune from accidents is also prone to unnecessary risk-taking to demonstrate skill. A combines contradictory attitudes. B pairs invulnerability with resignation, which are psychologically opposed. D combines impulsivity with its antidote (carefulness), which is contradictory. ### Q44: What is an indication for a macho attitude? ^t40q44 - A) Quick resignation in complex and critical situations - B) Careful walkaround procedure - C) Risky flight maneuvers to impress spectators on ground - D) Comprehensive risk assessment when faced with unfamiliar situations **Correct: C)** > **Explanation:** The correct answer is C because the macho attitude is characterised by performing risky manoeuvres to demonstrate skill or bravery, prioritising ego and external validation over safety. This actively creates hazardous situations that would otherwise never arise. A describes resignation (a different hazardous attitude). B and D describe safe, professional behaviours that are the opposite of macho behaviour. The antidote for macho is: "Taking chances is foolish." ### Q45: Which factor can lead to human error? ^t40q45 - A) Proper use of checklists - B) Double check of relevant actions - C) The bias to see what we expect to see - D) To be doubtful if something looks unclear or ambiguous **Correct: C)** > **Explanation:** The correct answer is C because confirmation bias -- the tendency to perceive and interpret information in ways that confirm pre-existing expectations -- is a major source of human error. Pilots may misread instruments, misidentify runways, or fail to notice abnormalities because the brain filters information through what it expects to see. A (checklists) and B (double checks) are error-prevention strategies. D (healthy doubt) is a protective attitude against errors, not a cause of them. ### Q46: Which is the best combination of traits with respect to the individual attitude and behaviour for a pilot? ^t40q46 - A) Introverted - stable - B) Extroverted - stable - C) Extroverted - unstable - D) Introverted - unstable **Correct: B)** > **Explanation:** The correct answer is B because extroversion supports effective communication, crew coordination, and the assertiveness needed for CRM, while emotional stability (low neuroticism) ensures calm, rational decision-making under pressure and consistent performance. A (introverted-stable) provides calmness but may lack the communication assertiveness needed in crew environments. C (extroverted-unstable) has good communication but unreliable emotional responses. D (introverted-unstable) combines poor communication with emotional unreliability. ### Q47: Complacency is a risk due to... ^t40q47 - A) Better training options for young pilots. - B) The high error rate of technical systems. - C) The high number of mistakes normally made by humans. - D) Increased cockpit automation. **Correct: D)** > **Explanation:** The correct answer is D because automation complacency occurs when pilots over-rely on automated systems, progressively reducing active monitoring of aircraft state. As automation becomes more sophisticated and reliable, vigilance decreases and manual flying skills degrade. When automation fails, the complacent pilot may be unprepared to take over. A (better training) reduces rather than increases complacency risk. B (high error rate) would actually maintain vigilance. C (human mistakes) is a general statement, not specifically linked to complacency. ### Q48: The ideal level of arousal is at which point in the diagram? See figure (HPL-002) P = Performance A = Arousal / Stress... ^t40q48 ![Yerkes-Dodson Curve](figures/HPL-002-yerkes-dodson.svg) - A) Point D - B) Point C - C) Point B - D) Point A **Correct: C)** > **Explanation:** The correct answer is C (Point B) because it represents the peak of the Yerkes-Dodson inverted-U curve where arousal is optimal and performance is maximised. A (Point D) is on the far right where excessive stress collapses performance. B (Point C) is past the peak in the declining region. D (Point A) is on the far left where too little arousal causes poor performance from boredom and inattention. The goal is to maintain arousal near Point B through workload management and stress coping techniques. ### Q49: At which point in the diagram will a pilot find himself to be overstrained? See figure (HPL-002) P = Performance A = Arousal / Stress... ^t40q49 - A) Point B - B) Point D - C) Point C - D) Point A **Correct: B)** > **Explanation:** The correct answer is B (Point D) because it represents the extreme right of the Yerkes-Dodson curve where stress and arousal are excessive, causing performance collapse. At this level, the pilot experiences tunnel vision, cognitive freezing, panic responses, and inability to process information effectively. A (Point B) is the optimal arousal point. C (Point C) shows moderate overarousal with declining but not collapsed performance. D (Point A) represents under-arousal, not overstrain. ### Q50: Which of these qualities are influenced by stress? 1. Attention 2. Concentration 3. Responsiveness 4. Memory ^t40q50 - A) 1 - B) .1, 2, 3 - C) 1, 2, 3, 4 - D) .2, 4 **Correct: C)** > **Explanation:** The correct answer is C because stress affects all four cognitive functions: attention narrows (tunnel vision), concentration becomes difficult to sustain, responsiveness is altered (initially faster, then degraded under extreme stress), and memory -- particularly working memory -- is impaired by elevated cortisol. This is why emergency procedures must be practised to automaticity: procedural (motor) memory is more resistant to stress than conscious declarative recall. A, B, and D are incomplete subsets. ### Q51: The proportion of oxygen in the air at sea level is 21%. What is this percentage at an altitude of 5 km (16,400 ft)? ^t40q51 - A) 5 % - B) 15 % - C) 10 % - D) 21 % **Correct: D)** > **Explanation:** The correct answer is D because the proportion (percentage) of oxygen in the atmosphere remains constant at 21% regardless of altitude. What decreases with altitude is the partial pressure of oxygen, because total atmospheric pressure drops. At 5 km, the air is still 21% oxygen, but the partial pressure is roughly half its sea-level value, which is why hypoxia occurs. A, B, and C all incorrectly suggest the percentage itself changes. ### Q52: The signs of oxygen deficiency... ^t40q52 - A) are right away clearly noticeable. - B) can appear from as low as 4000 ft altitude. - C) appear in smokers at lower altitudes than in non-smokers. - D) consist of extreme difficulty in breathing (gasping for air). **Correct: C)** > **Explanation:** The correct answer is C because smokers already have elevated carboxyhaemoglobin levels (CO bound to haemoglobin), which reduces the blood's effective oxygen-carrying capacity. This means hypoxia symptoms appear at lower altitudes than in non-smokers. A is wrong because hypoxia is insidious -- symptoms are often not clearly noticeable, which is precisely what makes it so dangerous. B is too low for initial symptoms in healthy individuals. D describes a late-stage or dramatic presentation that does not characterise the typical subtle onset. ### Q53: Carbon monoxide... ^t40q53 - A) is a by-product of the chemical energy production in cells: tissue absorbs oxygen and releases carbon monoxide. - B) has a sweet smell and bitter taste. It is only harmful in very high doses. - C) is toxic and results from incomplete combustion, e.g. a leaking exhaust system in an aircraft or incomplete gas combustion in a hot air balloon. - D) is, together with oxygen and hydrogen, one of the most important elements present in the atmosphere. **Correct: C)** > **Explanation:** The correct answer is C because carbon monoxide is a colourless, odourless, highly toxic gas produced by incomplete combustion. In aviation, it can enter the cockpit through leaking exhaust systems or heating systems. It binds to haemoglobin 200 times more readily than oxygen, creating carboxyhaemoglobin and preventing oxygen transport. A confuses CO with CO2 (carbon dioxide, the actual cellular waste product). B is completely wrong -- CO is odourless and harmful even in small concentrations. D is factually incorrect about atmospheric composition. ### Q54: How long does it generally take for the human eye to fully adapt to darkness? ^t40q54 - A) Approx. 30 minutes. - B) Approx. 1 hour. - C) Approx. 15 minutes. - D) Approx. 5 minutes. **Correct: A)** > **Explanation:** The correct answer is A because full dark adaptation (scotopic vision using rod cells) takes approximately 30 minutes. Cone cells adapt within about 7 minutes, but rods require the full 30 minutes to reach maximum sensitivity. Exposure to bright light resets the process. B (1 hour) overestimates the time. C (15 minutes) reflects only partial adaptation. D (5 minutes) represents only the initial cone adaptation phase. Pilots should avoid bright cockpit lighting and use red lighting to preserve night vision. ### Q55: Low blood pressure... ^t40q55 - A) mainly causes problems at rest in a lying position. - B) can cause dizziness. - C) is a recurring problem in elderly smokers. - D) causes absolutely no problems. **Correct: B)** > **Explanation:** The correct answer is B because hypotension can cause dizziness, particularly during changes of posture (orthostatic hypotension) when blood pools in the lower body upon standing. This is relevant in aviation because dizziness can mimic spatial disorientation. A is wrong because low blood pressure causes fewer symptoms at rest; problems arise during position changes. C describes hypertension (high blood pressure), which is more associated with elderly smokers. D is wrong because low blood pressure can cause significant symptoms. ### Q56: What symptom will most probably occur at 20,000 ft (6100 m) altitude without a pressurised cabin or oxygen equipment? ^t40q56 - A) Loss of consciousness. - B) Altitude sickness with pulmonary oedema. - C) Dyspnoea. - D) Fever. **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 5-12 minutes, with rapid progression to unconsciousness as blood oxygen saturation drops critically. B (altitude sickness with pulmonary oedema) develops over hours to days at moderate altitude during mountaineering, not within the timeframe of acute hypoxia at 20,000 ft. C (dyspnoea) may occur briefly but loss of consciousness is the dominant and most probable symptom. D (fever) is not caused by altitude. ### Q57: When flying with a severe head cold, sharp pain can affect the sinuses. This pain occurs... ^t40q57 - A) during descent. - B) with every notable change in flight altitude. - C) during climb. - D) during accelerations. **Correct: A)** > **Explanation:** The correct answer is A because during descent, external atmospheric pressure increases, compressing the air in the blocked sinuses. When the sinus ostia (openings) are swollen shut from a cold, air cannot enter to equalise the increasing external pressure, creating a painful pressure differential (sinus barotrauma). C (during climb) is less problematic because the expanding air inside the sinuses can usually force its way out even through partially blocked passages. B overgeneralises. D (accelerations) is not the primary trigger. ### Q58: Which are the symptoms of motion sickness (kinetosis)? ^t40q58 - A) High fever, vomiting, headache. - B) High fever, dizziness, watery diarrhoea. - C) Dizziness, sweating, nausea. - D) Watery diarrhoea, vomiting, headache. **Correct: C)** > **Explanation:** The correct answer is C because motion sickness manifests as dizziness, sweating, nausea, pallor, and potentially vomiting -- caused by conflicting sensory inputs between the visual and vestibular systems. A and B include high fever, which is a sign of infection, not motion sickness. B and D include watery diarrhoea, which is a gastrointestinal symptom not associated with kinetosis. The absence of fever is a key distinguishing feature. ### Q59: During a normal approach to an unusually wide runway, one may have the impression that the approach is being made... ^t40q59 - A) at too great a height. - B) at too high a speed. - C) at too low a speed. - D) at too low a height. **Correct: C)** > **Explanation:** The correct answer is C because an unusually wide runway appears closer and larger than expected, giving the visual impression of being lower than actual altitude. This can also translate into a perception of approaching too slowly, because the expected visual cues for a normal approach are distorted. The pilot may respond by either flying too high or increasing speed, both of which are inappropriate corrections. A and D describe height perceptions that are secondary to the speed impression asked about. B is the opposite of the typical illusion. ### Q60: Under positive g-forces, a greyout can occur which precedes blackout. Which organ is primarily affected by greyout? ^t40q60 - A) The lungs. - B) The eyes. - C) The brain. - D) The muscles. **Correct: B)** > **Explanation:** The correct answer is B because the eyes (specifically the retina) are the first organs affected during positive g-forces because the retina has the highest oxygen demand of any tissue and is particularly sensitive to reduced blood supply. As blood drains from the head under positive g, retinal arterial pressure drops below intraocular pressure, causing progressive loss of vision (grey-out) before the brain is affected (blackout/unconsciousness). A (lungs) are not the primary organ affected. C (brain) is affected later. D (muscles) are not primarily involved.