Disturbance (15k - 20k ft.) - physiological responses can no longer compensate for oxygen defficiency. Symptoms - impaired vision/ flight control/ handwriting/ coordination/ speech/ and memory, happy/mean drunk, hearing one of last senses to go.
Critical (>20k ft.) - happens within 3-5 min. Symptoms - loss of conciousness, convulsions, and then death.
Prevention of Hypoxic Hypoxia
limit time at altitude
use supplemental oxygen during night flights above 4k ft.
Treatment of Hypoxia
give 100% oxygen if possible
descend below 10k ft.
Self impossed stresses
- no self medicating, affect people differently, unwanted effects
Exhaustion - lack of rest/sleep/physical exercise
Alchohol - each ounce consumed raises physiological altitude by 2k ft.
Tobbaco - CO2 has a 200-300 time greater affinity for red blood cells then O2. Causes Hypemic Hypoxia. Smokers physiological alt at SL is 5k ft.
Hypoglycemia - low blood sugar. Use proper nutrition.
Considerations if using drugs
Predictable side effects
Middle ear discomfort
mainly experienced during a descent caused by trapped air expanding and contracting in the middle ear
Preventionswallow or yawn
Valsalva - close mouth, pinch nose, and blow(never valsalva while ascending)
if not remedied, descend very slowly
of not solved on ground, see flight surgeon
Spatial Disorientation def
an individuals innaccurate perception of position, attitude and motion relative to the surface of the earth (or significant objects; e.g. trees, buildings). The result causes the pilot not to believe his flight instruments. The pilot mistakenly believes his false senses.
a false perception of reality. Occurs when various sensory inputs that affect the brain disagree with each other
dizzy or spinning sensation
Types of SD
Type 1 - Unrecognizedmost dangerous type
aviator doesn't think anything is wrong
usually results in fatal crash
Type 2 - Recognizedpilot realizes something is wrong
pilot does not understand he is having SD
Type 3 - Incapacitatingpilot has overwhelming sensation of movement and cannot control the aircraft
3 types of sensory systems
most important sensory system
eye provides 80% of orientation info.
Fire, Fire, Fire CRASH CSAR
Altered planes of reference
Vestibular system (inner ear consists of:)
Otolith organs: small sensory hairs that respond to gravity and linear acceleration
Semicircular canals: sense changes in angular acceleration. Will react to roll, pitch, or yaw attitude
Somatogyral - caused by angular accelerative and decelerative flight
Somatogravic - caused by changes in linear accelerations and decelerations or gravity that stimulate the otolith organs
most common form of SD
pilot fails to recognize angular motioni during percieved straight and level flight
pilot quickly reacts once roll is noticed and this gives a sensation of rolling in the opposite way
AI shows a level attitude yet pilot feels as if he is still rolling
causes pilot to lean into the direction of the original roll
pilot unknowingly enters a descending turn which falsely stimulates the semicircular canals
once recognized, the PI corrects to straight and level flight, put the PI will percieve the aircraft is turning in the opposite direction
the Pi will correct for this false perception and reenter the original spin with increased rates of descent
PI enters a prolonged turn where the stimulated semicircular canal becomes equalized
PI makes a head motion on a different geometric plane other than that of the turn
the yaw axis semicircular canal is moved to another plane of rotation resulting in a sensation of a turn in the opposite direction and the fluid then stimulates the other two canals
the result is a perception of motion which creates a very strong tumbling sensation
When aircraft accels and decels, inertia causes the otolith organ to sense a noses high or low condition
the PI falsely corrects this perception by pulling aft (or forward) cyclic
occurs during upward acceleration
the eyes will track downward
the pilot senses the aircraft nose is going up
the pilot falsely corrects this perception by applying forward cyclic
opposite of elevator illusion. Occurs during downward movement of aircraft
the eyes will track upward
the PI senses the aircraft nose is going down
the PI falsely corrects this perception by applying aft cyclic
may occur when entering autorotation
another name is "seat of the pants" flying
this system of orientation is the result of pressure on joints, muscles, or skin
illusion may occur if the PI feels pressure on his body and misenterprets it for a climb/descent/ or turn
Never Never Avoid Trust
Never fly without visual reference points (horizon or AI)
Never try to fly VMC and IMC at the same time
Avoid fatigue, smoking, hypoglycemia, hypoxia, and anxiety which will aggrevate the illusion
Trust you instruments
Treatment of SD
Develop a good cross check; refer to instruments
Delay intuitive actions
state of feeling tired, weary, or sleepy that results from prolonged mental or physical work, extended periods of anxiety, exposure to harsh environments, or loss of sleep. Boring tasks may increase fatigue.
Types of Fatigue
Accute - fatigue experienced between 2 regular sleep periods.
Chronic - occurs over a long period of time and may be the result of inadequate recovery of successive periods of accut fatigue
Burnout (motivational exhaustion) - after a period of prolonged chronic fatigue, the person shuts down and ceases to function occupationally and socially. A complete lack of motivation.
What are the considerations for Distance Estimation and Depth Perception?
Monocular cues (GRAM)
Geometric Perspective (LAV)
Vertical position in the field
Retinal Image Size (KITO)
Known size of objects
Increasing/decreasing size of objects
Overlapping Contours or Interposition of Objects
Aerial perspective (FLP)
Fading of colors or shades
Loss of detail or texture
Position of light source and direction of shadow
What are the 3 types of vision?
Photopic occurs in daylight and bright light
produces sharp images and color vision
requires use of central vision
involves cones only
Mesopic occurs at dawn, dusk, and in full moonlight
reduces color vision and visual accuity
involves both rods and cones
Scotopic occurs on dimly lit nights
decreases visual accuity
causes loss of color interpretation
causes night blind spot
requires use of peripheral vision and recognition of object silhouettes
involves rods only
Night vision techniques
Off-Center Vision - look 10 degrees off object in any direction and no longer than 2-3 seconds for any technique
Scanning - Right to left or left to right or stop-turn-stop-turn patterns
Shapes or silhouttes - used to identify structures such as churches, mosques, or barn silos