Army Aeromedical Flashcards
The Flight Surgeon is a _____ crewmember.
Rated.
What is the timeframe that an FDME or FDHS must be started and completed?
Within a three-month period preceding the end of the birth month.
Who has the final approval authority of a DD Form 2992?
The Unit Commander
What is the difference of a temporary versus permanent medical disqualification?
Temporary results in requalification within 365 days. Permanent is not likely to result in requalification within 365 days.
What are the two types of FDME and how long are they valid for?
Initial (18 months) and comprehensive (5 years between 20-49 Yrs, 1 year at 50 yrs and older).
What are the immediate action steps for protective measures inside a cockpit if exposed to smoke or fumes?
Recognize Ventilate Descend Land Evacuate Seek medical attention
What component of the eye contains photoreceptors known as rods and cones?
Retina
This condition is a result of the eye’s actual focal point being behind the retinal plane or wall, causing blurred vision (e.g. nearby objects are not seen clearly).
Hyperopia (farsightedness)
The lens is fairly elastic and flexible in our twenties, however, as we age into our late forties, the lens begins to harden. This condition is known as:
Presbyopia
Which surgical procedure is less likely to cause permanent vision change due to the thickness of the flap?
LASEK
What is considered the most important cue to depth perception?
Motion Parallax
Objects near an aircraft appear to move more rapidly, while distant objects appear to be almost stationary
What does GRAM stand for?
Geometric Perspective (LAV)
Retinal Image Size (KITO)
Aerial Perspective (FLP)
Motion Parallax
What are the active and passive laser protective countermeasures?
Active:
Evasive Action
Scanning with one eye or monocular optics.
Passive: Take cover NVDS Squinting Protective Goggles
While landing at a private grass airstrip, your single-engine airplane touched down short of the runway. What visual illusion did you experience?
Size-distance Illusion
You are on a two-leg cross-country flight from Portland, Maine with a stop for fuel in Ohio. You start to experience deteriorating visibility from rain and sunset which caused you to slow your decent to maintain visual contact with the ground. You collide with a mountain crest at about 2000 ft. level. What visual illusion did you experience?
Structural Illusion
What are the three types of Spatial Disorientation?
•Unrecognized (most dangerous)
The pilot does not receive any indications of SD or think anything is wrong. The pilot fails to recognize and counteract.
•recognized
The pilot perceives a problem from SD, but might feel that the controls are malfunctioning or wrongly perceive an instrument failure
•incapacitating
The pilot experiences such an overwhelming sensation of movement that they cannot physically orient using visual cues or instruments.
What are the three systems that influence equilibrium?
Visual (80% of orientation, most important).
Vestibular (motion and gravity) - Semicircular canals detect changes in speed and direction. Otolith organs detect changes speed without a change in direction.
Proprioceptive - “flying by the seat of your pants” the body itself senses changes while flying from forces or pressures. Can be unreliable
What is the measure of the magnitude of an accelerative force with respect to gravity
A “g.” It is equal to 32.2 ft/s² or 9.81 m/s²
What is the rate of change of velocity with respect to time?
Acceleration
Define “Newton’s First Law of Motion”.
A body at rest tends to stay at rest, a body in motion tends to stay in motion, until acted upon by an outside force.
Define “Newton’s Third Law of Motion”.
For every action there is an equal and opposite reaction (inertial force)
What are some “Authorized Undergarments”?
Wear issued type 100% cotton 100% wool Nomex Any combination of three blends
Describe Flight Boot Characteristics and wear.
Retention Stability Protection for feet and ankles Fire retardant Leather boots must have upper construction of NOMEX, cotton All boots must have AWR Laced to top Avoid zippers, or straps
How are ID tags worn?
Worn around the neck while flying
Tucked between blouse and t-shirt (outside of collar)
NO silencers/covers
(550 cord or plastic)
Identify the structure of the atmosphere
Troposphere - sea level to 53,000 ft.
Stratosphere - Tropopause to 30 miles
Mesosphere - 30 to 50 miles
Thermosphere - 50 to 435 miles
What is the mean temperature lapse rate.
-1.98 degrees C per 1000 feet
What are the physiological zones of the atmosphere?
Efficient zone - Sea level to 10,000 feet (760 mm Hg to 523 mm Hg)
Deficient zone - 10,000 to 50,000 feet (523 mm Hg to 87mm Hg)
Space equivalent zone - 50,000 feet and above
What is the composition of the atmosphere?
78% Nitrogen (N2)
21% Oxygen (O2)
1% Other - 0.03% CO2
What are the oxygen requirements for flight in an unpressurized aircraft above 10,000 ft?
10,000 ft. - 1 hour of flight allowed before oxygen is required
12,000 ft. - 30 Minutes of flight allowed before oxygen is required
14,000 ft. - oxygen is required at all times
63,000 feet is know as what?
The Armstrong line. The point at which blood boils.
The measurement of pressure exerted on the earth’s surface from the gases and water in the atmosphere
Barometric Pressure
Define Hypoxia.
State of oxygen deficiency in the blood cells and tissues sufficient to cause impairment of function
What are the four types of hypoxia?
Hypoxic - Not enough O2 in the air or decreasing atmospheric pressure prevents diffusion.
Hypemic - Reduction in blood’s O2 carrying capacity due to blood loss or exposure to common monoxide.
Stagnant - Inadequate circulation (pressure points or G forces).
Histotoxic - inability of the tissue cell to accept or use oxygen (Cyanide, alcohol, or Narcotics)
List the Symptoms of Hypoxia (what you might feel)
Air hunger Apprehension Fatigue Nausea Headache Dizziness Blurred vision Hot & cold flashes Euphoria Belligerence Numbness Tingling Denial
List the Signs of Hypoxia (what you might see)
Hyperventilation Cyanosis Mental confusion Poor judgment Lack of muscle coordination
Methods to prevent hypoxia?
Limit time at altitude
Pressurized cabin
Minimize self imposed stressors
100% O2
How do you treat Hypoxia?
Descend to a safe altitude
100%O2
What are the Stages of Hypoxia? (ICDC)
Indifferent Stage 0-10,000 ft
Night vision deteriorates at about 4000 feet as well as visual acuity and night.
Compensatory Stage 10-15000ft
The circulatory and respiratory system compensates for hypoxia by increasing pulse, blood pressure, circulation rate, respiration rate. At 10,000-15,000 ft after 10-15 minutes, impaired efficiency may be obvious such as drowsiness and errors in judgment.
Disturbance Stage 15-20000 ft
Physiological responses can no longer compensate for oxygen deficiency. Fatigue, sleeping us, dizziness, headache, euphoria, reduced motor function, cyanosis
Critical Stage 20,000+ ft.
Within 3 to 5 minutes leads to mental confusion, dizziness, incapacitation, and eventually unconsciousness.
What is the time of useful consciousness at 18,000 ft.?
20 - 30 minutes
What is Hyperventilation?
An excessive rate (>16 breaths/min) and depth of respiration leading to the abnormal loss of CO2 from the blood (Alkalosis)
What is Gas Dysbarism?
Syndrome resulting from the effects, excluding hypoxia, of a pressure differential between the ambient barometric pressure and the pressure of gases within the body
Two Types: Trapped Gas and Evolved Gas
What is the treatment for Ear/Sinus Blocks?
On the ascent (rare):
Land and refer individual to flight surgeon
On the descent (most common): Stop the descent of the aircraft and attempt to clear by valsalva
If unable to clear, climb back to altitude until clear by pressure or valsalva
Descend slowly and clear ear frequently during descent
Identify the types of stressors.
- Psychosocial (job, illness, family)
- Cognitive (Mental/ self confidence/ dwelling on the past)
- Physiological (self imposed/ DEATH)
- Environmental (altitude, speed, temp
What is stress?
The nonspecific response of the body to any demand placed upon it
What are the physiological stressors/ self imposed stressor (DEATH)?
Drugs Exhaustion Alcohol Tobacco Hypoglycemia
Define Fatigue
The state of feeling tired, weary, or sleepy that results from periods of anxiety, exposure to harsh environment, activity, or loss of sleep
What are the three types of fatigue?
- Acute
- Chronic
- Motivational exhaustion (burnout).
Identify countermeasures for fatigue during periods of sleep restriction
- Strategic napping
- Rest breaks
- Exercise
- Postural Changes
What are the monocular cues associated with Geometric perspective (LAV)?
Geometric perspective means that objects appear to have different shapes when viewed at varying distances and angles
-
Linear Perspective
(parallel lines converge as distance from you increases) -
Apparent foreshortening
(an object’s shape appears elliptical when viewed from a distance) -
Vertical Position In the Field
(Objects at greater distances appear higher on the horizon than closer objects)
What are the monocular cues associated with Retinal Image Size (KITO)?
Rental image sizing is used in distance estimation.
-
Known size of objects
The nearer an object is, the larger its retinal image. The observer must know the objects actual size to make a comparison to it’s retinal image size. -
Increasing or decreasing size of objects
If the retinal image size increases, the object is moving closer. If the size decreases, the object is moving away. -
Terrestrial association
Comparing the size of one object, like an airfield, with an object of a known size like a helicopter, helps determine the size and distance of the object from the observer -
Overlapping contours
When objects overlap, the overlapped object is further away
Identify aeromedical policy for use of medications for fatigue while on flight status
All hypnotics and other sleep aids are Class 4 medications when in general use
- Cannot be used without consent of FS
- Grounded while using.
- Need a waiver for underlying condition
Pre-deployment rest or sustained operations
- FS may give medications for short-term use
- No waiver is required
- Stimulant or rest agents only used in combat or during exceptional (“fly or die”) circumstances of operational necessity
_____ are used primarily for day or high intensity light vision
Cones
_____ are used for night or low intensity light vision
Rods
The center of the retina, called the _____ contains a very high concentration of cone cells, but no rod cells
The concentration of rod cells begin to increase toward the retina’s periphery
Fovea
The chemical _____ is always present within cone cells. _____ allows cone cells to immediately respond to visual stimulation, regardless of the ambient light level
Iodopsin
Rod cells contain an extremely light sensitive chemical call ______. Also called “visual purple”.
_____ is not always present in the rods, because light bleaches it out, and renders the rods inactive to stimulation. This is what causes dark adaption to reset.
Rhodopsin
Rhodopsin
The average time required to gain the greatest sensitivity or adaption to a dark environment is ____ to ____ minutes
30 to 45 minutes
The Day Blindspot originates where the optic nerve attaches to the _____.
No cones or rods are present at the attachment point, therefor no vision
Retina
The three types of light adaptation, and viewing periods associated with army aviation are _____, _____, _____
Photopic (Daylight or bright lights)
Mesopic (Dawn, dusk, full moonlight)
Scotopic (lowlight, partial moonlight, starlight)
This type of vision involves cones only. It produces the sharpest visual acuity.
Requires use of central vision.
Photopic Vision
This type of vision occurs at dawn, dusk, and full moon light.
Involves both rods and cones
Has reduced color vision and visual acuity as light decreases
Is the most dangerous type of vision
Mesopic
This type of vision is experienced in low light environments (star/moonlight)
Cones are ineffective, causing poor resolution and detail
Visual acuity decreases to 20/200
Color perception is lost
Peripheral vision is primarily used
Scotopic
The ____ Blindspot occurs when the fovea becomes inactive.
The fovea is center of the retina and it contains a very high concentration of cone cells, but no rod cells. So if there is low light, there is nothing to detect light in the center of the retina.
This is why off center viewing must be used at night because no light can be detected directly where you look.
Night blindspot
The size of the night Blindspot (Increases/ decreases) as the distance between the eyes and object increases
Increases
This means the night Blindspot can hide larger objects as the distance between you and the object increases
_____ is also known as nearsightedness.
The eye’s focal point is in front of the retinal plane, causing blurred vision. Thus, distant objects are not seen clearly, and only nearby objects are in focus
Myopia
After exposure to a bright light, the degree of impairment depends on the _____ and _____ of the exposure
Intensity and duration
Complete dark adaptation recovery time can range from several minutes to _____ minutes or longer following an extremely bright or long light exposure
45
Rods are least affected by the color ____ light. This is why we use this color of light at night to preserve night vision. (But we ALWAYS preflight with a ____ light to allow us to see spills and colored fluids)
Red
White
Adverse effects on night vision begin at _____ ft pressure altitude. Hypoxia significantly reduces rod sensitivity, increases dark adaptation time, and decreases night vision.
4,000 ft. PA.
What are the monocular cues associated with Aerial Perspective
• Fading of colors or shades
An object viewed through haze or smoke appears at a greater distance than it actually is. A beautiful day can make an object appear closer than it is
• Loss of detail or texture
The further an object is from an observer, the less aparent discreet details become
• Position of light and shadow direction
If an objects shadow is cast toward an observer, the object is closer to the observer than the light
Visual illusions: False Horizon
A pilot confuses a wide plane of reference such as sloping cloud tops, mountain ranges, coast lines with the true horizon.
All visual illusions:
False horizon
Confusion with ground lights
Height depth perception
Crater illusion
Structural illusion
Size distance illusion
Auto kinesis
:)
Visual illusions: Confusion with ground lights
A pilot, mistakes ground lights for stars, placing the aircraft in an unusual attitude to keep the misperceived ground lights above the aircraft.
Visual illusions: Height Depth Perception
Caused by an absence or insufficient, visual cues, causing pilot to miss judge depth perception, causing pilots to fly, dangerously low to the ground.
Flying over areas devoid of visual reference, such as deserts, snow, water
Visual illusions: crater illusion
Landing under NVGs with the infrared search light too far under the nose. Creates illusion of landing upwards in all directions, or being in a crater.
Visual illusions: Structural Illusion
Caused by the effects of rain, snow, sleet, heat waves, etc. Causing a straight line to appear curved.
The curved windshield can also cause this.
Visual illusions: Size-Distance
A crewmember misinterprets an object of unfamiliar size and shape by comparing it with that they are accustomed or familiar to seeing.
Landing at an unfamiliar runway that is narrower than expected can cause the pilot to think they are higher and further away than they are.
A wider runway than expected may cause a pilot to think they are closer than they really are, causing them to fly the approach to high and land long
A downsloping runway can create the illusion that the aircraft is lower than it actually is, leading to a higher approach as the pilot tries to correct the runway to a “normal sight picture”
An upsloping runway can create the illusion that the aircraft is higher than it actually is, leading to a lower approach as the pilot tries to correct the runway to a “normal sight picture”
Visual illusions: Autokinesis
Occurs at night with minimal light as a dim light is seen against a dark background. After about 6 to 12 seconds of visually fixating on the light, an individual may perceive movement, although there is no actual objects displacement.
This illusion occurs if a pilot enters a slow roll. They may fail to receive the aircraft is no longer flying straight and level. Once the pilot notices the bank, they may make a quick recovery to resume straight and level flight. However, the pilot may now perceive that the aircraft is banking in the opposite direction
The Leans
This illusion occurs is a pilot enters a moderate or steep angle turn and remains in it for several seconds. The semi-circular canals (which react to only changes in velocity) will eventually reach equilibrium, and no motion will be perceived.
Upon abruptly recovering from the bank, the pilot may have a strong sensation of initiating a bank in the opposite direction, even if the instruments contradict this.
The pilot may disregard the instruments, and Control against the falsely perceived turn, causing the aircraft to re-enter a spiral in the direction of the original turn.
Graveyard Spiral
1 ounce of alcohol can have a physiological altitude of _____ ft.
Smoking can cause a physiological altitude of _____ ft. This is higher because red blood cells bind 200-300x more easily to Carbon monoxide than to oxygen
2,000 ft.
5,000ft
Time of you useful consciousness at 25,000 ft is ____ to ____ minutes
With rapid decompression at 25,000 ft this decrease to ____ to ____ minutes
4-6 minutes
2-3 minutes
