Disorientation Flashcards
Types of disorientation
Type 1 - Unaware - Aware of incorrect perception and accident
Type 2 - Aware - correct and ok
Type 3 - Incapacitated - Accident
Risk factors that contribute to SD
Degraded visuals
- Night, IMC, High Altitude, Featureless terrain, NVGs
Accelerations
- Subthreshold change
- Sustained or prolonged turns
Human
- Fatigue, Distractions, high workload, illness/medication.
Describe otoliths organs function
Linear acceleration
Tilt sensation
Gravity sensor
Describe Semicircular canals function
Angular acceleration
Visual stability
Sense of turning/rotation
Define somatogravic illusion
Causes: otoliths and proprioception in dark night take off.
Confusion of linear translation and tilt.
EgAcceleration can be mistaken at pitching up.
“ misinterpretation of lateral acceleration as pitching up on take off and pitch down to correct causing crash.”
Prevent by preparedness and discipline instrument scan.
Define the Leans
False sensation of roll attitude Pilots lean to dispel the sensation Due to semilunar canal Occur on subthreshold roll Rolling out of prolonged turn Prevent it by: awareness, leans toward
EG: slow roll subthreshold movement and then correction then above threshold soo feel uneven.
Define somatogyral illusion
Due to semi-circular canals
False sensation of rotation when still
No sense of rotation when turning.
May overcorrect and re enter speed was out if poor visual cue.
it happens due to poor visual cues
Spin recovery post prolonged turning
“Graveyard spin or spiral”
How to prevent: preparedness, avoid prolonged spins, trust your instructment
Define G Excess Illusion
Horizontal otoliths.
When in roll and turn head to view confirmed hit under G force
This cause Horizontal linear movement eg coming out of roll.
Pilot responses by tightening the turn.
Define Coriolis
Rare
When: head movement in a turning aircraft.
Due to semi circular canal
When in turn atstable speed and then the pilot moves head in another plane changing angular acceleration to another semicircular canal giving pilot feeling of movement in the wrong way.
Displacement of otoliths - coriolis force
Strong unpleasant sensation of tumbling and nausea.
How to prevent it: preparation, minimise head movement in a turn. Maximise eye movements. Return head to original position
Define Flicker vertigo
Rotating or flickering light
Flas sense of rotation in a direction opposite to the movin light
Define alternobaric vertigo
Spinning sensation caused by a difference in pressure between the left and right middle ear
Define central errors
Break off phenomenon - feeling of detachment, isolation or physical separation while flying
Knife edge - increase awareness of aircraft movement
Giant hand - inability to make control inputs
The semi circular canal detect A. Angular acceleration B. Linear acceleration C. Movement of the eyes D. Acceleration due to gravity
Angular acceleration
A somatogravic illusion generally produce a false sense of A. Roll attitude B.Yaw attitude C. Pitch attitude D. Rotation
D. Rotation
What is the subthreshold for acceleration detect in order for the semicircular canals
2 deg/sec/sec
What illusion are caused by the semicircular canals
Somatogyral
Coriolis
Leans
Describe the vestibule-ocular reflex
Allows us to keep an eye on target when moving our head
Movement detected in semicircular canals in pasted to vestibular nuclei and then to the extra ocular muscle to move the eyes
Very fast
Describe the otoliths organs
2 in each ear
- utricle and saccule
Aligned horizontal and vertical (detect gravity) plane
Detect linear accelerometers
Summary the systems that the body used for orientation
Vision: dominant sense, peripheral retina, streaming cues
Otoliths organs: linear acceleration, tilt sensation, gravity sensor
Proprioception: joints, muscles, tendons, skin, touch, pressure, joint position, muscle stretch, vibration, gravity
Semicircular canals: angular acceleration, visual stability, sense of turning/rotation
Define Spatial disorientation
The failure to correctly sense the position, motion or attitude of yourself, or your aircraft, in relation to gravity and the earth’s surface.
Prevent strategies for aircrews to prevent SD
Preparation - awareness of missions nd flight conditions, recognise threats, use AVRM - transition early onto instruments, verify their information - stay on them until you have good visual cues - ASORs Proficiency - Maintain proficiency in instrument flying - don’t fly by seat of the pants - Instrumentation and cockpit factor - emergency recovery training Physiology - Physical health - mental health - manage fatigue - avoid alcohol - avoid self medication - safe prescribed meds - I’M SAFE checklist
Management of disorientation
Take immediate action Defer non-essential tasks Get on instruments, make them “read right” Avoid unnecessary head movements Maintain straight and level flight Advise ATC/Declare emergency Transfer aircraft control Abandon aircraft?
