I85PREP
⌘ K
AOBPM Preventive Medicine study materials
AOBPM Preventive Medicine study resources

AOBPM Preventive Medicine practice questions

One question at a time. Build your AOBPM Preventive Medicine understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Aerospace Medicine

At what cabin altitude does the FAA generally require supplemental oxygen for the flight crew when flying unpressurized aircraft?

  1. Above 10,000 ft cabin altitude at any time Correct answer.
  2. Above 18,000 ft cabin altitude at any time
  3. Above 14,000 ft cabin altitude at any time
  4. Above 12,500 ft cabin altitude for more than 30 minutes

Explanation

Federal aviation regulations require the pilot to use supplemental oxygen whenever cabin pressure altitude exceeds 10,000 ft. Time-based provisions apply to passengers above 12,500 ft and to crew above 14,000 ft in some contexts, but the baseline crew threshold is 10,000 ft.

Question 2Aerospace Medicine

Which gas law best explains why a trapped gas expansion in the middle ear can cause barotrauma during ascent?

  1. Henry's law
  2. Dalton's law
  3. Boyle's law Correct answer.
  4. Charles's law

Explanation

Boyle's law states that at constant temperature, gas volume is inversely proportional to pressure. As ambient pressure falls during ascent, trapped gas expands and can injure the middle ear if it cannot vent.

Question 3Aerospace Medicine

A pilot breathing 100% oxygen at sea level has an alveolar oxygen partial pressure closest to which value?

  1. About 40 mmHg
  2. About 100 mmHg
  3. About 673 mmHg Correct answer.
  4. About 160 mmHg

Explanation

At sea level with 100% oxygen, alveolar PO2 approximates the inspired oxygen pressure minus water vapor and CO2 contributions, yielding roughly 670 mmHg. This is far above the ~100 mmHg seen breathing air.

Question 4Aerospace Medicine

Which condition is the most common cause of in-flight incapacitation among airline pilots?

  1. Gastrointestinal illness Correct answer.
  2. Psychiatric disorders
  3. Cardiovascular events
  4. Neurologic events

Explanation

Gastrointestinal disorders, particularly infectious gastroenteritis, are the most frequently reported cause of sudden incapacitation in flight. Cardiovascular events are less common but carry higher fatality risk.

Question 5Aerospace Medicine

What is the primary purpose of the Valsalva maneuver during a descent?

  1. To equalize pressure across the middle ear Correct answer.
  2. To reduce sinus pressure
  3. To increase oxygen saturation
  4. To lower heart rate

Explanation

The Valsalva maneuver raises nasopharyngeal pressure, forcing air through the Eustachian tube to equalize the pressure difference across the tympanic membrane during descent. This prevents or relieves middle ear barotrauma.

Question 6Aerospace Medicine

Which symptom pattern is most characteristic of decompression sickness after a dive followed too soon by flight?

  1. Isolated fever
  2. Sudden hearing loss
  3. Symmetrical ascending paralysis
  4. Joint pain with skin mottling Correct answer.

Explanation

Decompression sickness classically presents with joint pain (the bends), skin mottling, and other systemic symptoms from nitrogen bubble formation. Neurologic symptoms can occur but the joint and skin findings are typical.

Question 7Aerospace Medicine

Which factor most increases the risk of spatial disorientation in flight?

  1. Flying in instrument meteorological conditions without reference to instruments Correct answer.
  2. Flying with a copilot
  3. Flying in visual meteorological conditions
  4. Flying with a functioning attitude indicator

Explanation

Spatial disorientation is most likely when visual references are lost and the pilot relies on unreliable vestibular cues. Instrument meteorological conditions without instrument cross-check create this vulnerability.

Question 8Aerospace Medicine

Which is the recommended initial approach to managing a conscious pilot with suspected hyperventilation during flight?

  1. Apply positive pressure breathing
  2. Descend rapidly and remove oxygen
  3. Increase breathing rate to raise oxygen
  4. Administer 100% oxygen and coach slower breathing Correct answer.

Explanation

Hyperventilation is managed by reassuring the pilot, slowing the breathing rate, and administering oxygen to address any coexisting hypoxia. Hypoxia must be excluded because it can mimic hyperventilation.

Question 9Aerospace Medicine

What is the primary mechanism by which positive pressure breathing at altitude impairs venous return?

  1. Increased blood viscosity
  2. Reduced hemoglobin affinity
  3. Increased intrathoracic pressure reduces cardiac filling Correct answer.
  4. Decreased alveolar oxygen content

Explanation

Positive pressure breathing raises intrathoracic pressure, which impedes venous return to the heart and can reduce cardiac output. This is why pressure breathing systems use counter-pressure garments at high altitudes.

Question 10Aerospace Medicine

A pilot experiences a sudden loss of cabin pressure at 35,000 ft. What is the most important immediate action to protect against hypoxia?

  1. Turn off the seatbelt sign
  2. Increase cabin temperature
  3. Don oxygen mask and initiate emergency descent Correct answer.
  4. Reduce engine power

Explanation

At high altitude, time of useful consciousness is very short, so donning oxygen and beginning an emergency descent to a breathable altitude are the critical immediate actions. Delaying either action risks incapacitation.

Question 11Aerospace Medicine

Which statement best describes the time of useful consciousness at 40,000 ft for a pilot breathing ambient air?

  1. About 15 minutes
  2. About 30 minutes
  3. About 15 to 20 seconds Correct answer.
  4. About 3 to 5 minutes

Explanation

At 40,000 ft, time of useful consciousness is very short, on the order of 15 to 20 seconds. This underscores the need for immediate oxygen use and rapid descent.

Question 12Aerospace Medicine

Which finding is most consistent with the early stage of hypoxic hypoxia in a pilot?

  1. Euphoria and impaired judgment Correct answer.
  2. Severe chest pain
  3. Localized muscle paralysis
  4. Cyanosis and bradycardia

Explanation

Early hypoxia often produces euphoria, reduced judgment, and a sense of well-being that impairs self-recognition of the problem. This makes objective monitoring and oxygen discipline essential.

Question 13Aerospace Medicine

Which of the following best explains the increased risk of decompression sickness at altitude after diving?

  1. Higher oxygen partial pressure causes bubbles
  2. Increased humidity causes bubble formation
  3. Lower ambient pressure promotes nitrogen bubble formation Correct answer.
  4. Lower carbon dioxide levels cause bubbles

Explanation

Reduced ambient pressure at altitude decreases nitrogen solubility, promoting bubble formation from residual tissue nitrogen after a dive. Adequate surface intervals before flight are therefore required.

Question 14Aerospace Medicine

A pilot with a middle ear infection asks about flying. What is the most appropriate advice?

  1. Avoid flying until the condition resolves and Eustachian tube function is normal Correct answer.
  2. Fly as long as symptoms are mild
  3. Use decongestants and fly regardless
  4. Fly only at low cabin altitudes

Explanation

Eustachian tube dysfunction from infection impairs pressure equalization and increases barotrauma risk. Flying should be deferred until the condition resolves and equalization is demonstrated.

Question 15Aerospace Medicine

Which visual illusion occurs when a pilot approaches a runway that is narrower than usual?

  1. Somatogravic illusion
  2. Runway width illusion causing a lower approach Correct answer.
  3. Black hole effect
  4. Autokinesis

Explanation

A narrower-than-usual runway can create the illusion of being higher than actual, prompting a lower approach. Conversely, a wider runway can produce a high approach.

Question 16Aerospace Medicine

Which physiological effect is associated with prolonged exposure to noise in the aviation environment?

  1. Increased visual acuity
  2. Reduced risk of fatigue
  3. Noise-induced hearing loss Correct answer.
  4. Improved low-frequency hearing

Explanation

Chronic exposure to high noise levels causes noise-induced hearing loss, often beginning at high frequencies. Hearing protection and exposure limits are important preventive measures.

Question 17Aerospace Medicine

Which is the most appropriate preventive measure for a pilot at risk of spatial disorientation during night flight?

  1. Rely on physical sensations
  2. Maintain instrument cross-check and proficiency Correct answer.
  3. Fly without reference to instruments
  4. Increase head movement to improve orientation

Explanation

Spatial disorientation is prevented by trusting instruments and maintaining proficiency in instrument cross-check, especially when visual cues are degraded. Physical sensations are unreliable in flight.

Question 18Aerospace Medicine

Which factor most increases the risk of hypoxia during flight in a pressurized aircraft?

  1. Cabin altitude of 2,000 ft
  2. Cabin temperature of 22°C
  3. Cabin altitude above 8,000 ft Correct answer.
  4. Relative humidity of 20%

Explanation

Cabin altitudes above 8,000 ft reduce alveolar oxygen pressure and can cause hypoxia, particularly in susceptible individuals. Pressurized aircraft are designed to keep cabin altitude within acceptable limits.

Question 19Aerospace Medicine

Which statement about circadian rhythm disruption in aviation is most accurate?

  1. It has no effect on performance
  2. It is resolved by caffeine alone
  3. It affects only older pilots
  4. It can be mitigated by strategic napping and light exposure Correct answer.

Explanation

Circadian disruption from crossing time zones or night flying impairs performance and can be mitigated by strategic napping, light exposure, and scheduling. These countermeasures help align the body clock with duty periods.

Question 20Aerospace Medicine

Which is the most accurate statement about fatigue risk management in aviation?

  1. Fatigue is best addressed by willpower alone
  2. Fatigue has no effect on error rates
  3. Fatigue only matters for long-haul flights
  4. Fatigue risk management uses scheduling, rest, and education as countermeasures Correct answer.

Explanation

Fatigue risk management combines scheduling controls, adequate rest opportunities, and education to reduce fatigue-related errors. It is a systems approach rather than an individual responsibility alone.

Question 21Aerospace Medicine

Which is the primary reason for using a counter-pressure garment during high-altitude pressure breathing?

  1. To lower body temperature
  2. To maintain venous return and prevent blood pooling Correct answer.
  3. To increase lung volume
  4. To reduce oxygen consumption

Explanation

Counter-pressure garments apply external pressure to the body, supporting venous return and preventing blood pooling when positive pressure breathing raises intrathoracic pressure. This helps maintain cardiac output and consciousness.

Question 22Aerospace Medicine

A pilot reports transient visual blurring and tunnel vision during a high-G maneuver. Which mechanism best explains these symptoms?

  1. Elevated intraocular pressure
  2. Reduced cerebral perfusion from impaired venous return Correct answer.
  3. Increased cerebral blood flow
  4. Excess oxygen in the retina

Explanation

High sustained G forces reduce venous return and cardiac output, lowering cerebral perfusion and causing visual symptoms such as tunnel vision or greyout. Anti-G straining maneuvers and protective equipment help maintain perfusion.

Question 23Aerospace Medicine

Which statement best explains the interaction between alcohol and hypoxia at altitude?

  1. Alcohol has no effect on altitude tolerance
  2. Alcohol impairs judgment and worsens hypoxia effects at altitude Correct answer.
  3. Alcohol increases the threshold for hypoxia symptoms
  4. Alcohol improves oxygen saturation

Explanation

Alcohol impairs judgment and coordination and can worsen the effects of hypoxia at altitude, reducing effective performance. This is why alcohol is prohibited within specified intervals before flight.

Question 24Aerospace Medicine

Which is the most accurate description of the somatogravic illusion during takeoff acceleration?

  1. A false sensation of pitching up leading to nose-down input Correct answer.
  2. A false sensation of pitching down leading to nose-up input
  3. A false sensation of yaw
  4. A false sensation of roll

Explanation

Linear acceleration during takeoff can be misinterpreted by the otolith organs as a pitch-up sensation, prompting the pilot to push the nose down. This illusion is dangerous during night or instrument departures.

Question 25Aerospace Medicine

Which statement best describes the relationship between cabin altitude and oxygen saturation in a healthy pilot?

  1. Oxygen saturation increases with cabin altitude
  2. Oxygen saturation is unrelated to cabin pressure
  3. Oxygen saturation remains unchanged at all cabin altitudes
  4. Oxygen saturation declines as cabin altitude increases above a threshold Correct answer.

Explanation

As cabin altitude rises, alveolar oxygen pressure falls and oxygen saturation declines, particularly above about 8,000 ft. This relationship underlies cabin altitude limits and oxygen requirements.

Question 26Aerospace Medicine

What is the primary physiological mechanism responsible for barotitis media during a descent in flight?

  1. Rapid expansion of trapped gas in the inner ear
  2. Increased cerebrospinal fluid pressure transmitted to the cochlea
  3. Excessive oxygen diffusion into the middle ear space
  4. Failure of the Eustachian tube to equalize pressure in the middle ear Correct answer.

Explanation

Barotitis media occurs when the Eustachian tube cannot equalize pressure between the middle ear and the changing cabin pressure, typically during descent when external pressure rises. This leads to a pressure gradient that causes pain, fluid accumulation, and possible hemorrhage. The other options do not describe the mechanism of middle ear barotrauma.

Question 27Aerospace Medicine

Which preflight action is most effective for reducing the risk of decompression sickness in a pilot who has recently engaged in scuba diving?

  1. Drinking caffeinated beverages to increase alertness
  2. Performing a series of stretching exercises before boarding
  3. Breathing 100% oxygen for 30 minutes before the flight
  4. Observing a surface interval of at least 24 hours after diving before flying Correct answer.

Explanation

The recommended surface interval before flying after diving is at least 24 hours to allow residual nitrogen to be eliminated and reduce the risk of decompression sickness at altitude. Breathing oxygen or stretching does not adequately replace the need for a sufficient surface interval. Caffeine does not prevent decompression sickness.

Question 28Aerospace Medicine

Which statement best describes the effect of alcohol consumption on hypoxia tolerance at altitude?

  1. Alcohol has no effect on hypoxia tolerance but impairs motor skills
  2. Alcohol increases the threshold for hypoxia symptoms, leading to earlier impairment
  3. Alcohol improves oxygen saturation by dilating pulmonary vessels
  4. Alcohol decreases the threshold for hypoxia symptoms, leading to later recognition Correct answer.

Explanation

Alcohol depresses the central nervous system and blunts the early symptoms of hypoxia, so a pilot may not recognize hypoxia until it is more severe. This decreased threshold for symptoms delays corrective action. Alcohol does not improve oxygen saturation or increase the hypoxia threshold.

Question 29Aerospace Medicine

What is the primary purpose of a counter-pressure garment (G-suit) for pilots?

  1. To reduce the risk of decompression sickness by maintaining external pressure
  2. To provide thermal insulation at high altitude
  3. To prevent venous pooling in the lower extremities during high-G maneuvers Correct answer.
  4. To assist with breathing during positive pressure ventilation

Explanation

A G-suit applies pressure to the legs and abdomen to reduce venous pooling and maintain venous return to the heart during high-G maneuvers, thereby helping to prevent G-induced loss of consciousness. It does not provide thermal insulation, assist breathing, or prevent decompression sickness.

Question 30Aerospace Medicine

Which visual illusion is most likely to cause a pilot to fly a lower-than-normal approach path?

  1. False horizon
  2. Black hole illusion Correct answer.
  3. Runway width illusion
  4. Autokinesis

Explanation

The black hole illusion occurs when there is no visual reference between the aircraft and the runway, often at night over water or unlit terrain, leading the pilot to fly a lower approach than intended. Runway width illusion affects height perception based on runway width, autokinesis is the apparent movement of a stationary light, and false horizon is a misperception of the horizon.

Question 31Aerospace Medicine

Which of the following is the most appropriate action to prevent spatial disorientation during flight in low visibility?

  1. Trust the flight instruments and cross-check them regularly Correct answer.
  2. Look outside for visual references as much as possible
  3. Rely on vestibular sensations to maintain orientation
  4. Perform gentle head movements to improve vestibular function

Explanation

In low visibility, vestibular sensations can be misleading, so pilots must rely on flight instruments and maintain a regular scan to prevent spatial disorientation. Looking outside may not provide reliable references, and head movements can exacerbate disorientation.

Question 32Aerospace Medicine

Which statement best describes the effect of cabin altitude on oxygen saturation in a healthy pilot at rest?

  1. Oxygen saturation remains at sea-level values up to 10,000 ft
  2. Oxygen saturation increases as cabin altitude rises due to hyperventilation
  3. Oxygen saturation is unaffected by cabin altitude until 14,000 ft
  4. Oxygen saturation decreases significantly at cabin altitudes above 5,000 ft Correct answer.

Explanation

In a healthy individual, oxygen saturation begins to decrease noticeably at cabin altitudes above 5,000 ft due to the lower partial pressure of oxygen. At 10,000 ft, saturation is typically around 90% or lower. It does not remain at sea-level values or increase with altitude.

Question 33Aerospace Medicine

Which is the most accurate statement regarding the use of continuous positive airway pressure (CPAP) by a pilot with obstructive sleep apnea?

  1. CPAP is acceptable if the pilot is stable and compliant with treatment Correct answer.
  2. CPAP is disqualifying for all classes of medical certification
  3. CPAP must be discontinued at least 24 hours before flight
  4. CPAP is only allowed for private pilots

Explanation

For pilots with obstructive sleep apnea, CPAP therapy is generally acceptable for medical certification if the condition is stable and the pilot is compliant with treatment, as documented by a specialist. It is not universally disqualifying, nor is it limited to private pilots.

Question 34Aerospace Medicine

A pilot flying at 8,000 ft cabin altitude begins to feel euphoric and has difficulty concentrating. What is the most likely explanation?

  1. Hyperventilation due to anxiety
  2. Carbon monoxide poisoning
  3. Mild hypoxia Correct answer.
  4. Decompression sickness

Explanation

At 8,000 ft cabin altitude, the partial pressure of oxygen is reduced, which can cause mild hypoxia, manifesting as euphoria, impaired judgment, and difficulty concentrating. Hyperventilation would typically cause dizziness and tingling, while carbon monoxide poisoning and decompression sickness have different presentations.

Question 35Aerospace Medicine

Which of the following is the most effective way to prevent noise-induced hearing loss in aviation?

  1. Taking frequent breaks in quiet areas
  2. Using noise-canceling headsets or earplugs Correct answer.
  3. Limiting flight time to less than 2 hours per day
  4. Increasing cabin altitude to reduce noise

Explanation

Noise-induced hearing loss is best prevented by reducing exposure to high noise levels through the use of hearing protection such as noise-canceling headsets or earplugs. Limiting flight time or taking breaks may help but are less effective than direct protection.

Question 36Aerospace Medicine

What is the primary mechanism by which positive pressure breathing at altitude can impair venous return?

  1. It decreases heart rate through vagal stimulation
  2. It causes vasodilation of peripheral vessels
  3. It increases intrathoracic pressure, reducing blood flow to the heart Correct answer.
  4. It increases oxygen saturation, leading to vasoconstriction

Explanation

Positive pressure breathing increases intrathoracic pressure, which compresses the great veins and reduces venous return to the heart, potentially leading to decreased cardiac output and hypotension. The other options do not describe the primary mechanism.

Question 37Aerospace Medicine

Which statement best describes the somatogravic illusion during takeoff acceleration?

  1. It causes a sensation of rolling left, leading the pilot to bank right
  2. It causes a sensation of pitching down, leading the pilot to pull the nose up
  3. It causes a sensation of pitching up, leading the pilot to push the nose down Correct answer.
  4. It causes a sensation of yawing, leading the pilot to apply rudder

Explanation

The somatogravic illusion occurs during rapid acceleration, such as takeoff, when the otolith organs misinterpret the horizontal acceleration as a pitch-up sensation. The pilot may then push the nose down, potentially leading to a dangerous descent. It does not cause sensations of pitch down, roll, or yaw.

Question 38Aerospace Medicine

Which of the following is the most appropriate advice for a pilot who has a middle ear infection and is scheduled to fly?

  1. Fly only if symptoms are mild
  2. Do not fly until the infection resolves and Eustachian tube function is normal Correct answer.
  3. Use decongestants and fly as scheduled
  4. Fly at lower cabin altitudes to reduce pressure changes

Explanation

A middle ear infection can impair Eustachian tube function, increasing the risk of barotrauma during flight. Pilots should not fly until the infection has resolved and normal ear function is restored. Decongestants may help but do not guarantee safe equalization.

Question 39Aerospace Medicine

Which factor most increases the risk of hypoxia in a pressurized aircraft?

  1. Increased physical activity
  2. Use of supplemental oxygen
  3. Failure of the cabin pressurization system Correct answer.
  4. Flying at a lower cabin altitude

Explanation

The most significant risk for hypoxia in a pressurized aircraft is a failure of the pressurization system, which can lead to a rapid decrease in cabin pressure and a drop in oxygen partial pressure. Lower cabin altitude, physical activity, and supplemental oxygen do not increase hypoxia risk.

Question 40Aerospace Medicine

What is the recommended initial approach to managing a conscious pilot with suspected hyperventilation during flight?

  1. Administer 100% oxygen and instruct the pilot to breathe slowly Correct answer.
  2. Have the pilot breathe into a paper bag to increase carbon dioxide
  3. Increase the cabin altitude to reduce oxygen levels
  4. Administer a sedative to calm the pilot

Explanation

For suspected hyperventilation, the initial approach is to administer 100% oxygen and coach the pilot to slow their breathing, as hyperventilation may be accompanied by hypoxia. Breathing into a paper bag is not recommended in flight due to the risk of worsening hypoxia. Sedatives are not appropriate.

Question 41Aerospace Medicine

A pilot experiences sudden severe vertigo and nausea during a climb in instrument meteorological conditions. Which is the most likely cause?

  1. Hypoxic hypoxia
  2. Decompression sickness
  3. Alternobaric vertigo due to unequal middle ear pressure Correct answer.
  4. Carbon monoxide poisoning

Explanation

Alternobaric vertigo occurs when there is unequal pressure between the middle ears, often during climb or descent, leading to vertigo and nausea. Decompression sickness, hypoxia, and carbon monoxide poisoning do not typically present with sudden vertigo in this context.

Question 42Aerospace Medicine

Which statement best describes the relationship between cabin altitude and the risk of decompression sickness in a pilot with a recent dive?

  1. Lower cabin altitudes increase the risk by increasing oxygen levels
  2. Decompression sickness risk is only related to dive depth, not cabin altitude
  3. Cabin altitude has no effect on decompression sickness risk
  4. Higher cabin altitudes increase the risk by reducing ambient pressure Correct answer.

Explanation

Higher cabin altitudes correspond to lower ambient pressure, which increases the likelihood of nitrogen bubble formation in a pilot with residual nitrogen from a dive. Lower cabin altitudes reduce the risk. Cabin altitude does affect risk, and dive depth is not the only factor.

Question 43Aerospace Medicine

Which of the following is the most appropriate prevention strategy for a pilot at risk of spatial disorientation during night flight?

  1. Fly at higher altitudes to improve visual references
  2. Use a disciplined instrument scan and avoid sudden head movements Correct answer.
  3. Rely on vestibular senses and avoid instrument reference
  4. Increase cabin lighting to reduce contrast

Explanation

Prevention of spatial disorientation at night involves relying on instruments with a disciplined scan and minimizing head movements that can provoke vestibular illusions. Relying on vestibular senses is dangerous, and higher altitude or cabin lighting do not directly prevent disorientation.

Question 44Aerospace Medicine

Which statement best describes the time of useful consciousness (TUC) at 40,000 ft for a pilot breathing ambient air?

  1. It is typically 1 to 2 minutes
  2. It is typically 3 to 5 minutes
  3. It is typically 10 to 15 minutes
  4. It is typically 15 to 20 seconds Correct answer.

Explanation

At 40,000 ft, the time of useful consciousness is very short, typically 15 to 20 seconds, due to the extremely low partial pressure of oxygen. This highlights the critical need for immediate oxygen supplementation in case of depressurization.

Question 45Aerospace Medicine

Which of the following best explains the interaction between alcohol and hypoxia at altitude?

  1. Alcohol depresses the central nervous system, masking hypoxia symptoms Correct answer.
  2. Alcohol decreases blood flow to the brain, reducing hypoxia effects
  3. Alcohol increases respiratory rate, improving oxygenation
  4. Alcohol increases the affinity of hemoglobin for oxygen

Explanation

Alcohol is a central nervous system depressant that can mask the early symptoms of hypoxia, leading to delayed recognition and more severe impairment. It does not increase hemoglobin affinity, improve oxygenation, or reduce hypoxia effects.

Question 46Aerospace Medicine

A pilot flying at 25,000 ft without supplemental oxygen experiences impaired judgment and euphoria. Which stage of hypoxia is this?

  1. Compensatory stage
  2. Death stage
  3. Critical stage
  4. Indifferent stage Correct answer.

Explanation

The indifferent stage of hypoxia is characterized by impaired judgment, euphoria, and lack of self-awareness, often occurring at altitudes around 12,000 to 15,000 ft or higher. The compensatory stage involves increased heart rate and respiration, while the critical stage involves severe impairment.

Question 47Aerospace Medicine

Which of the following is the most accurate statement regarding the use of over-the-counter antihistamines by pilots?

  1. They have no side effects at altitude
  2. They can cause drowsiness and impair performance, so their use should be evaluated Correct answer.
  3. They are only a concern for pilots over 60
  4. They are always acceptable because they are available without prescription

Explanation

Many over-the-counter antihistamines can cause drowsiness and impair cognitive and motor performance, especially in the aviation environment. Their use should be carefully evaluated, and pilots should consult an aviation medical examiner. They are not always acceptable or free of side effects.

Question 48Aerospace Medicine

At what cabin altitude does the FAA require supplemental oxygen for the flight crew when flying above it?

  1. 15,000 ft
  2. 14,000 ft
  3. 12,500 ft Correct answer.
  4. 10,000 ft

Explanation

FAA regulations require the flight crew to use supplemental oxygen at cabin altitudes above 12,500 ft for more than 30 minutes, and at all times above 14,000 ft. The 10,000 ft threshold is for passengers, while 14,000 ft is the continuous requirement for crew.

Question 49Aerospace Medicine

Which gas law explains why a partially filled oxygen cylinder cools as it is rapidly discharged?

  1. Boyle's law
  2. Henry's law
  3. Dalton's law
  4. Charles's law Correct answer.

Explanation

Charles's law states that the volume of a gas is directly proportional to its temperature at constant pressure. When gas is rapidly released from a cylinder, it expands and does work, causing a drop in temperature (adiabatic cooling). Boyle's law relates pressure and volume, Dalton's law deals with partial pressures, and Henry's law concerns gas solubility.

Question 50Aerospace Medicine

Which of the following is the earliest symptom of hypoxia in most individuals?

  1. Chest pain
  2. Euphoria Correct answer.
  3. Cyanosis
  4. Bradycardia

Explanation

Euphoria, often accompanied by a sense of well-being and impaired judgment, is frequently the first noticeable symptom of hypoxia. Cyanosis is a late sign and unreliable, bradycardia may occur later, and chest pain is not a typical early hypoxic symptom.