Aeromedical factors

State of feeling weary, tired or sleepy that results from prolonged mental or physical work, extended periods of anxiety, exposure to harsh environments or lack of sleep.

• 1 - Acute (2-3 reg sleep periods)
• -Inattention
• -Errors
• -Irritation
• -Recover with one regular sleep period
• 2 - Chronic (inadequate successive sleep periods)
• -Insomnia
• -Depressed mood
• -Irritability
• -Weight Loss
• -Poor Judgement
• -Loss of appetite
• -Slowed reaction time
• -Poor motivation
• -Recovery may require several weeks
• 3 - Motivational Exhaustion (aka burnout)
• -body shuts down and ceases functioning occupationaly, and socially

• 1. Control sleep environment
• 2. Adjust to shift work
• 3. Good Health and fitness
• 4. Moderate use of alcohol and caffeine
• 5. Good nutrition
• 6. Time management
• 7. Realistic planning
• 8. Optimal working conditions
• 9. Naps

Rest and natural sleep

Body's nonspecific response to any demand placed upon it

• 1. Psychosocial
• -Life events
• -Work
• -Illness
• -Family issues
• 2. Environmental
• -Altitude (5000' and below)
• -Speed
• -Temp
• -Aircraft design
• 3. Physiological (DEATH)
• -Drugs
• -Exhaustion
• -Alcohol
• -Tobacco
• -Hypoglycemia and poor nutrition
• 4. Cognitive
• -How one perceives a problem

• Emotional - anxiety, irritability
• Behavioral - work performance, motivation, suicide
• Cognitive - Concentration, judgment
• Physical - heart rate, blood pressure, breathing

• 1. Mental skills required
• 2. Stress characteristic of situation
• 3. Physical and psychological make-up of individual

• 1. Avoid stressors (most important)
• 2. Change your thinking
• 3. Learn to relax
• 4. Ventilate stress

• Self-medicated
• Overdose
• Allergic reactions
• Predictable side effects
• Synergistic effects
• Caffeine

• Lack of rest
• Physical condition

• 12 hours bottle to brief and no residual effects
• 1 ounce pure alcohol = 2,000' PA
• Could cause histotoxic hypoxia
• How it affects a person depends on:
• -amount consumed
• -Rate of obsorption
• -metabolism

• Adds 5,000' physical altitude
• Decreases night vision 20%
• Causes hypemic hypoxia

Individual's inability to determine his position, attitude, and motion relative to the surface of the earth or other significant objects

• I - Unrecognized **most dangerous
• -Doesn't perceive problem exists
• II - Recognized
• -Perceives a problem, may not recognize it as spatial D, Example-perceives control malfunction or instrument failure
• III - Incapacitation
• -Unable to reorient himself

• 1. Visual (80%)
• 2. Vestibular (15%)
• 3. Proprioceptive (5%)

FFFCRASHSCAR

• False Horizon
• Fascination/Fixation
• Flicker Vertigo
• Crater Illusion
• Reversible Perspective
• Auto kinesis
• Size-distance Illusion
• Height-depth perception
• Structural Illusion
• Confusion with ground lights
• Altered planes of reference
• Relative motion

• 1. Somatogyral
• -changes in angular acceleration/deceleration
• -Semicircular canals

• 2. Somatogravic
• -gravic - gravity (up and down) to remember it works linearly
• -changes in linear acceleration/deceleration
• -Stimulates otolith organs

• 1. Leans (most common)
• 2. Graveyard spin (Usually fixed wing)
• 3. Coriolis effect (most dangerous)

• Most common
• -Pilot fails to perceive angular motion
• -Occurs when rolling into or out of a bank
• -Pilot after coming out of a turn, will feel in an unusual attitude despite that he's straight and level and feel the need to turn aircraft back to the wrong turn attitude

• Usually fixed wing
• -Pilot enters a spin, recovers from the spin, feels as though he is spinning in the other direction, so reenters the initial spin direction.

• Most Dangerous
• -Overwhelming disorientation
• -Aircraft is in a turn, when the pilot moves head in a plane other than that of the turn, this creates new perception in 3 different planes: pitch, roll and yaw and causes head over heels tumbling feeling

• -Acceleration/deceleration
• -Acceleration: pilot feels nose up -pitches aircraft down
• -Deceleration: pilot feels nose low - pitches aircraft up

• Think 'loa' - 'lower' - aircraft going down
• -Occurs when aircraft is going down
• Aircraft goes down -eyes track up- pilot senses nose low/down - pilot pitches aircraft nose up

• Occurs when aircraft is going up
• -Aircraft goes up - eyes track down- pilot senses nose up- pilot pitches aircraft nose down

Sensation of spinning/dizziness

false perception of reality

When pilot becomes unable to read instruments properly

• 1. Always trust instruments
• 2. Never fly VMC and IMC at the same time
• 3. Never fly without visual referenes
• 4. Avoid stressors (fatigue, smoking, hypoglycemia, hypoxia, and anxiety)

• 1. Refer to the instruments & develop a good cross check
• 2. Delay intuitive actions
• 3. Transfer flight controls

• During descent, pressure of external air is greater than the pressure in the middle ear -> eardrum is forced inward
• More susceptible with a cold or sore throat, sinusitis etc. and descending altitude
• Pressure differential increases appreciable, impossible to open Eustachian tub -> causes eardrum to rupture
• Descents* most evident at altitudes below 5,000'
• -30,000->20,000 - mild discomfort
• -15,000-> 5,000 - great distress (larger change in barometric pressure)

• Don't fly with cold or sore throat, sinusitis, etc.
• Descend at slow/normal rate
• Clear your sinuses early & often by swallowing, yawning, and tensing muscles in the throat

• Stop descent & attempt Valsalva
• (Note: to prevent over pressurization, never do Valsalva during ascent)
• If not cleared:
• -climb to altitude until cleared by pressure change or valsalva
• -Reduce the rate of descent and equalize the ears & sinuses frequently during descent
• -Contact flight surgeon if condition persists after flight

Meds: allowed to self medicate with drugs approved by APL for flying duties

Anesthesia: local - 12 hours; general, spiral, or epidural - 48 hours

Alcohol: 12 hours + not residual effects

Immunizations: 12 hours, if reaction is experienced ->see flight surgeon

CS/Tear gas: no residual effects and local effects have resolved

Blood/Plasma donation: (*cannot donate regularly) blood (200 cc+) 72 hours; plasma - 24 hours; bone marrow - see flight surgeon

Decompression/Hypobaric chambers: hypobaric chambers at alt above 25,000': if flying at cabin pressure less than 10,000' - no restrictions; if flying at cabin pressure above 10,000 - 24 hour restriction

Diving Hyperbaric chambers: 24 hours; decompression sickness experienced: see Flight Surgeon

Simulator sickness: 12 hours after full recovery restriction before participating in real flight

Centrifuge runs: 6 hours + no residual effects

Hypoxia - Lack of Oxygen in the body

• 1. Hypoxic -Not enough oxygen in air
• -Prevents diffusion of O2 from lungs to blood stream (i.e. altitudes)
• 2. Hypemic -Reduction in Oxygen carrying capacity (*smokers blood can't cary much)
• -Reduce hemoglobin available to combine with oxygen (ie. carbon monoxide, anemia, blood loss, etc)
• 3. Stagnant -Lack of circulation
• -Heart failure and arterial spasm predispose individual to stagnant (ie. high G forces)
• 4. Histotoxic -Due to interference with the use of oxygen
• -Alcohol, narcotics and certain poisons interfere with cell's ability to use an adequate supply of O2

• 1. Indifferent (0-10,000)
• 2. Compensatory (10-15,000)
• 3. Disturbance (15-20,000)
• 4. Critical (20-25,000)

• 1. Indifferent (0-10,000')
• a. Decrease in night vision at 4,000'
• b. 90-98% O2 saturation

• 2. Compensatory (10-15,000')
• a. Drowsiness
• b. Poor judgment
• c. Impaired coordination
• d. Impaired efficiency
• e. 80-89% O2 saturation

• 3. Disturbance (15-20,000')
• a. Impaired flight control
• b. Impaired handwriting
• c. Impaired speech
• d. Decreased coordination
• e. Impaired vision
• f. Decreased memory
• h. Impaired judgment
• i. 70-79% saturation

• 4. Critical Stage (20-25,000')
• a. Circulatory failure
• b. CNS failure
• c. Convolsions
• d. Cardiovascular collapse
• e. Death
• f. 60-69% O2 saturation

• Limit time at altitude
• Use supplemental oxygen
• Pressurize the cabin

• Give individual 100% Oxygen
• If not available, descend to below 10,000'
• If symptoms persist, cause needs to be determined and treated

• -Covers an area of 5.5 to 7.5 degrees about 15 degrees from the fovea
• -Due to oval shape of the optic nerve combined with its offset position
• -Have at all times
• -Not normally noticed unless one eye is closed
• -Compensated by binocular vision

• -Occurs when fovea becomes inactive due to a concentration of cones in the fovea centralis and parafovea
• -5-10 degrees wide in the center of the visual field
• -Size of the night blind spot increases as the distance between the eyes and the object increases
• -Compensated by off-center viewing and proper scanning

• 1. Myopia (nearsightedness)
• a. Error in refraction in which the lens of the eye doesn't focus an image directly on the retina
• b. Focal point of the eye is in front of the retinal wall
• c. May be corrected by NVGs
• 2. Night myopia
• a. With regards to viewing blue-green light at night
• 3. Hyperopia (farsightedness)
• a. Focal point of the eye is behind the retinal wall
• b. May be corrected by NVGs
• 4. Astigmatism
• a. Unequal curvature of the cornea lens
• b. Inability to focus different meridians simultaneously
• c. Cannot be corrected by NVGs
• 5. Presbyopia
• a. PRES, think PRESidents are old, old has to deal with aging process
• b. Part of the normal aging process
• c. Causes lens to harden
• d. Visual functions that decline
• -glare sensitivity
• -recovery from glare
• -dynamic acuity
• -function under low illumination
• -information processing
• 6. Retinal Rivalry
• a. Experience the problem when both eyes try to simultaneously perceive two dissimilar objects independently

• False Horizon Illusion
• Fascination/fixation
• Flicker Vertigo
• Crater Illusion
• Relative Motion
• Auto kinesis - Occurs at night when focusing too long at a light
• Size Distance Illusion
• Height-Depth Perception Illusion - loses depth perception due to lack of sufficient visual cues
• Structural Illusions
• Confusion with ground lights
• Altered planes of reference
• Reversible Perspective

• Photopic - daylight/high level of artificial illumination
• -Produces sharp images and color vision
• -Involves cones only
• -because of high light level, rhodopsin is bleached out, and rods are less effective
• Mesopic - dawn, dusk, and under full moonlight
• -Reduces color vision and decreases visual acuity
• -Involves both rods and cones
• -Visual acuity decreases
• -Use off-center viewing and proper scanning techniques
• Scotopic - low light conditions (partial moonlight and starlight conditions)
• -Occurs on dimly lit nights
• -Decreases visual acuity and causes loss of color perception
• -Visual acuity: 20/200 (person needs to stand 20' to see what can be normally seen at 200'
• -Causes night blind spot
• -Involves the rods only (cones ineffective)
• -Requires use of peripheral vision

• Definition - Biochemical process in which the eyes become more sensitive to lower light levels
• -Individuals dark adapt at different degrees and rates

• Starting Level
• -The lower the starting level, the faster the dark adaptation
• -Exposed to 2-5 hours of bright sun: up to 5 hours to fully dark adapt
• -Exposed to more than 2-5 hours high light level, or consecutive days of 2-5 hours exposure: may take consecutive days of up to 5 hours to fully dark adapt

• Sensitivity
• -Rods are 1000X more sensitive than cones
• -When fully dark adapted, rods are 10,000X more sensitive than at the starting level
• -When fully dark adapted with pupil dilated, the total eye is 100,000X more sensitive than at the starting level.

• Time
• Time to dark adapt: 30-45 minutes
• Time to readapt after NVGs: 2-3 minutes to regain the dark adaptation level you were at when you first looked through the NVGs
• Time to readapt after high-intensity lighting: 5-45 minutes (depending on duration and intensity)

• Precautions at airfields
• Oxygen supply
• Red lens goggles and Lighting
• Sunglasses
• Cockpit lighting
• High Intensity lighting
• Exterior lighting
• Light flash compensation