LECTURE 9 ORIENTATION & MOTION SICKNESS AHF 2203 – AVIATION HUMAN FACTOR.

LECTURE 9ORIENTATION & MOTION SICKNESSAHF 2203 – AVIATION HUMAN FACTOR

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.

Situational awareness is similar to orientation.

But it includes: Awareness of what’s going on with

other aircraft Weather ATC Cockpit communication.

Introduction - Orientation

1. Visual

2. Vestibular

3. Proprioceptive

ALL THREE SYSTEMS INTERGRATE TO FORM A COMPLETE MENTAL PICTURE 4

Three Sensory Inputs for Orientations

Vision

Organs equilibrium located in the inner ears

Receptors located in the skin muscles, tendons and joins

Continue. . . .5

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

WHAT IS DISORIENTATION?

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.

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.

Types of DISORIENTATION

There are 5 types of DISORIENTATION, which are:

1. Postural disorientation 2. Positional disorientation – related to

position3. Temporal disorientation – related to time4. Spatial disorientation – related to motion5. Vestibular disorientation – related to

Vestibular system6. Visual Illusion – related to Vision system

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

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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

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2. Positional disorientation

Means the pilot is lost and doesn’t know his position (disoriented).

Thus, he unable to take effective corrective action.

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Temporal means related to time. It is direct function of how fast the brain

process the information

3. Temporal disorientation

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.

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Spatial Disorientation

5. VESTIBULAR DISORIENTAT

ION

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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.

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Vertigo is the inability of a person to perceive his/her position relative to the earth.

5. Vestibular disorientation

In other wordshe/she cannot tell which way is

UP!!!

Vestibular System

The Vestibular system is located in the inner ear. There

are two related structures, which are:1. Semicircular Canals:

Consists of three canals, Each canal is a bony, fluid-filled structure.

Enlarged area containing a sensory structure.

2. Otolith Organs: One of the particles in the inner ear. It helps maintain equilibrium relative to the

gravity.

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AuditoryNerve

Otolith Organs

Eustachian Tube

Opening to Throat

Ossicles

Middle EarEar Drum

External Ear

Cochlea

Semicircular Canals

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Vestibular System20

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.

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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

Vestibular System

Semicircular canals response to Roll, Pitch and Yaw

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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

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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.

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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.

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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.

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 in level flight, the otolith organs sense a nose-high attitude, which cause the pilot to pitch the aircraft down.

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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.

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.

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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.

6) Visual illusions - Auto kinesis

6) Visual illusions – Landing illusions

Landing Illusions – Sloping runway

6) Visual illusions – Landing illusions

Landing Illusion – Runway width

6) Visual illusions – Weather Condition

Weather condition such as haze, fog and others may cause visual illusion.

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.

6) Visual illusions – False Horizon

6) Visual illusions – False Horizon

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?

Part 2: Motion Sickness

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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.

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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

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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).

Major Causes of Motion Sickness

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)

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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

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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.

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