1. Lecture 9 orientation & motion sickness
AHF 2203 – AVIATION HUMAN FACTOR

2. Introduction - Orientation
Orientation = relative position
Is the key element in preventing aviation accidents.
If the plane works, and the pilot is not impaired, then the only other significant ingredient in safe flight for the trained pilot is maintaining orientation of the plane and himself.

3. Introduction - Orientation
Situational awareness is similar to orientation.
But it includes:
Awareness of what’s going on with other aircraft
Weather
ATC
Cockpit communication.

4. Three Sensory Inputs for Orientations
1. Visual
Vision
2. Vestibular
Organs equilibrium located in the inner ears
Body Senses Which Assist in Maintenance of Balance / Equilibrium
Vision is Most valid sense for maintaining orientation
3. Proprioceptive
Receptors located in the skin muscles, tendons and joins
ALL THREE SYSTEMS INTERGRATE TO FORM A COMPLETE MENTAL PICTURE 4

5. Continue
All three systems integrate to form a complete mental picture
Body Senses Which Assist in Maintenance of Balance / Equilibrium
Vision is most valid sense for maintaining orientation

6. WHAT IS DISORIENTATION?

7. Disorientation
Disorientation is lack of orientation or also can be said as lack awareness of the situation.
Individual will not be able to:
Determine position
Flight Attitude
Motion relative to earth surfaces
Disorientation is a leading cause of more than 15 percent of reported accidents.
No. of ways pilots can suffer from illusions
Misinterpretation of the info  vision is most important contributor to perception of orientation)
E.g. pilot may interpret sloping cloud base as level horizon
Misidentifications of ground lights (group of ships in the sea as stars) All above making inaccurate mental mode/interpretation
Correlation of the vestibular sense with the visual sense is optimized for ground based existence
In aircraft, the visual, vestibular, and proprioceptive systems may receive conflicting information, refer to different origins (earth horizon, cockpit), and may be operating outside the expected parameters.
SD is said to occur if a person loses the ability to determine orientation relative to the surface of the earth and objects.

8. Disorientation When disorientation affected pilot:
Pilots are unable to see, believe, interpret, or prove the information derived from their flight instruments.
Instead, they rely on the false information that their senses provide.

9. Types of DISORIENTATION
There are 5 types of DISORIENTATION, which are:
Postural disorientation
Positional disorientation – related to position
Temporal disorientation – related to time
Spatial disorientation – related to motion
Vestibular disorientation – related to Vestibular system
Visual Illusion – related to Vision system

10. 1. Postural disorientation
There are receptors within our skin, muscles, tendons, and joints that detect changes in relative position, pressure, and up and down changes of our posture.
Every time a muscle contracts or relaxes, tendons are pulled or released and joints move.
Proprioceptive signals are those generated by these changes.
All these inputs, which are continuously coming to the brain, tell the position of the pilot.
*tendon: organ that connect muscle and bone

11. 1. Postural disorientation
Posture also can be sensed by VESTIBULAR system (Organs equilibrium located in the inner ears).
In flight, these signals can conflict and be confusing to the mind, giving false interpretations and leading to DISORIENTATION.
Acceleration causes a feeling of pressure in various parts of the body

12. 2. Positional disorientation
Means the pilot is lost and doesn’t know his position (disoriented).
Thus, he unable to take effective corrective action.

13. 3. Temporal disorientation
Temporal means related to time.
It is direct function of how fast the brain process the information

14. 4. Spatial Disorientation
Spatial Disorientation is defined as illusions associated with relative motion.
Spatial means how the pilot is oriented to the horizon as either straight and level, in a turn, or climbing or descending (a visual orientation in a given space).
Vision is the source to determine balance and orientation. It will tell you how to react when you are in motion.
It will mislead you into an illusion of your own motion.
spatial disorientation defines illusions or perceived positions associated with relative motion, often called vection illusions.
Vection: relative motion to the eyes between the body and external object,
often an illusion of motion
Furthermore, spatial implies a visual orientation in a given space: how the pilot is oriented to the horizon as either straight and level, in a turn, or climbing or descending

15. Spatial Disorientation

16. 5. Vestibular disorientation

17. 5. Vestibular disorientation
Disorientation because of the Vestibular System not functioning well.
The most severe and intense feeling of instability and unbalance.
Can cause the Motion Sickness to the pilot, crew and passengers.
When pilot experiencing vestibular disorientation, it is called as VERTIGO.
Otolith Organs:
Monitor linear acceleration
Located in same bony labyrinth as semicircular canals
Composed of sensory hairs
Hairs project into a membrane containing crystalline particles
Gravity causes particles to bend hair cells

18. 5. Vestibular disorientation
Vertigo is the inability of a person to perceive his/her position relative to the earth.
In other words
he/she cannot tell which way is UP!!!

19. Vestibular System
The Vestibular system is located in the inner ear. There
are two related structures, which are:
Semicircular Canals:
Consists of three canals, Each canal is a bony, fluid-filled structure.
Enlarged area containing a sensory structure.
Otolith Organs:
One of the particles in the inner ear.
It helps maintain equilibrium relative to the gravity.

20. Vestibular System Semicircular Canals Otolith Organs Auditory Cochlea
Nerve
Ossicles
Ear Drum
Middle Ear
External Ear
Eustachian Tube
Opening to Throat 20 19 20 19

21. Vestibular System 1. Semicircular Canals
Semicircular Canals is sensitive to angular acceleration .
Angular acceleration is the change in both speed and direction .
It detects yaw, pitch, and roll motions.
Otolith organs Stimulated by linear acceleration: A change in speed without a change in direction 21 26 21 26

22. Vestibular System 2. Otolith Organs
The Otolith organs is sensitive to linear acceleration and deceleration (forward, aft, up, and down)
Linear accelerations is the change in speed without a change in direction

23. Semicircular canals response to Roll, Pitch and Yaw

24. Vestibular Disorientation
Vestibular disorientation will lead towards vestibular illusion.
Vestibular illusions is an inaccurate models of orientation.
There are four types vestibular illusions:
Coriolis iIlusion
Leans iIlusion
Occulogravic illusion
Rotational illusion
Illusion: False Belief

25. a) Coriolis Ilusion
Coriolis – Circular motion of wind as it passes over a rotating earth.
Coriolis illusion is caused by the sudden change
to the VESTIBULAR system
It occurs due to aircraft angular acceleration that affect the flow of fluids inside the semicircular canals.
It is dangerous illusion as it overwhelming sense of disorientation.
Can occur in any phase of flight especially during the beginning of turn for climb and descend.
Most severe vestibular illusion occurs when the semicircular canal fluid flows in two planes of rotation simultaneously
The aircraft must be turning
Rapid head movement

26. a) Coriolis Illusion
If pilot turn his head in different direction of aircraft turn, he will disoriented and confuses either aircraft were in a roll or yaw
To avoid, do not move your head too fast in limited visibility or darkness.

27. b) Leans Illusion
Leans Illusion is the false movement sense, can occurs when the pilot senses a bank angle when the aircraft is actually in level flight.
The leans can easily occur if the pilot not pay attention to the cockpit instrument.

28. c) Occulogravic Illusion: A false sensation of climbing
Oculogravic: in conditions of acceleration, sense of nose high or low and correction in pitch in a direction opposite the sensation.
When an aircraft accelerates or decelerates in level flight, the otolith organs sense a nose-high attitude relative to gravity
If that sensation is acted upon by the pilot without cross-checking instruments, he might pitch the aircraft down.
Deceleration causes a similar sensation of a nose-low attitude.
When an aircraft accelerates in level flight, the otolith organs sense a nose-high attitude, which cause the pilot to pitch the aircraft down.

29. d) Rotational Illusion
Also called angular motion illusion.
It caused by mis- information from a constant-rate turn (spin).
The pilot will disorientated and unable to control his actions.
Can cause the aircraft loss of control.
Also called angular motion illusion, rotational illusions result from misinformation from a constant-rate turn, as in a spin.
If the turn is at a constant rate, the fluid in the canals returns to its original stable position of equilibrium.
This results in the pilot’s perception that the turn has stopped.
When the turn slows (a change as in acceleration) or the aircraft levels off, the fluid is once again displaced but this time in the opposite direction.
The “graveyard spiral” is a condition most likely to affect fixed-wing aircraft pilots.
Upon recovering from the turn (or spin in this case) as just described, the pilot will undergo deceleration, which will be sensed by the canals and interpreted as a spin or turn in the opposite direction.
A loss of altitude in a prolonged constant rate turn may be interpreted as a wings level descent, which can lead you to increase elevator back pressure and tighten the turn, increasing your altitude loss.
A recovery to wings level flight may produce the illusion that the airplane is in a turn in the opposite direction, resulting in a reentry of the spiral.
This feeling must be fought until the fluid in your semicircular canals quits moving again.
The pilot’s instruments will tell him that he is not spinning, but he will have a strong sensation that he is.
If there is no outside reference to the horizon and the pilot disregards or doesn’t believe the instruments, he will be tempted to make control corrections against the falsely perceived spin so that he reenters a spin in the original direction.
Often the conflict is noticed, but the sensory input, even though erroneous, is overpowering, and the pilot is unable to control his actions.
This action is compounded by the pilot’s noting a loss of altitude as the spin develops and applying back pressure on the controls and adding power in an attempt to gain altitude.
This tightens the spin to the point where recovery is nearly impossible.
In a graveyard spiral, the angular velocity is in the form of a coordinated turn rather than a spin.
Remaining in this turn long enough (perceived as a constant-rate coordinated turn), that sensation of turning will be lost, and the flight will continue as a spiral.
A proper recovery from a spin that has ceased stimulating the motion sensing system can crate the illusion of spinning in the opposite direction.
The disorientated pilot will return the aircraft to its original spin

30. 6) Visual illusions
Visual illusions affect what the pilot perceives solely through vision, which in turn determines how he or she will respond.
Illusions of this kind are a greater source of misguidance in a flying activity such as judging landing height and distances
Examples of visual illusions are:
Autokinesis, Landing visual illusion, Weather condition leads illusion and False horizon.

31. 6) Visual illusions - Auto kinesis
Auto kinesis is the perception of false movement when a static source of light is looked at by the pilot for a period of time (minutes).
This moving reference point (an illusion) could lead the pilot to visually follow it.
It is felt that the cause is the brain’s and eyes’ attempts to find some other point of reference in an otherwise featureless visual field.
Prevention is a combination of realizing the eyes must focus on other objects at varying distances, not fixating on one target, and basic scanning.

33. 6) Visual illusions – Landing illusions
Landing Illusions – Sloping runway

34. 6) Visual illusions – Landing illusions
Landing Illusion – Runway width

35. 6) Visual illusions – Weather Condition
Weather condition such as haze, fog and others may cause visual illusion.

36. 6) Visual illusions – False Horizon
A false horizon can occur when the natural horizon is obscured or not readily apparent.
It can be generated by confusing bright stars and city lights.
It can also occur while flying toward the shore of an ocean or a large lake.
Because of the relative darkness of the water, the lights along the shoreline can be mistaken for stars in the sky.

37. 6) Visual illusions – False Horizon

38. 6) Visual illusions – False Horizon
Imagine if you fly at night in across a city which have bright light like this, would you be able to distinguish between star lights and ground like location?

39. Part 2: Motion Sickness

40. Introduction – Motion Sickness
Motion sickness occurs when man is exposed to real and unfamiliar motion.
Normally experienced by training’s pilot or passengers.
Pilot and passengers will feel uneasiness because a bit of anxiety, unfamiliarity.

41. Major Causes of Motion Sickness
Motion sickness is caused by continued stimulation of the tiny portion of the inner ear (vestibular system) which controls your sense of balance/equilibrium.
Several factors that can affect the vestibular system are:
When exposed to unfamiliar motion.
During turbulent weather

42. Major Causes of Motion Sickness
Some of the other additional common causes include
Heart discomfort
Anxiety
Observing or smelling someone else who is airsick
Eating foods that are nauseating (disgusting).

43. Symptoms of Motion Sickness
It causes nausea (tendency to vomit).
The symptoms are progressive. First, you lose your desire for food.
Then saliva collects in your mouth and you begin to sweat freely.
Eventually, you become nauseated and disoriented.
Your head aches and you may have to vomit.
Finally, can become incompletely incapacitated (incapacitated: prevent from functioning in a normal way)

44. Prevention & Treatment
Drink Enough Water
Use supplemental oxygen
Loosen tight fitting clothing
Limit head movement, avoid unnecessary movement
Focus on a point outside of aircraft
If severe, cancel flight and landing aircraft

45. Conclusion For summarization disorientation is caused by:
Vestibular system not functioning well and resulting to the false sensation to the pilot
Misinterpretation of visual information.
Motion sickness occurs when man is exposed to real and unfamiliar motion. Normally experienced by training’s pilot or passengers because a bit of anxiety, unfamiliarity.