Ch 12 - Perception And Perceptual Errors Flashcards by Logan Bibb

Perception

Based off past experience and knowledge (previous and learnt)

“We can perceive only that which we can conceive”

When perception matches reality, we are Situationally Aware

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2 Stages of perception:

Bottom Up; given to us through our senses (CNS -> brain)

Top Down; to perceive based off knowledge and past experience

In reality we are doing both; Interactive Processing

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Gestalt - 5 Laws of Perception

The whole is greater than the sum of its parts

1 - Continuity - objects that form a continuous form are perceived to be together or in the same group

2- Periodicity - fill in the gaps

3 - Proximity - closer together, we see as part of the same group

4 - Similarity - Objects similar in appearance appear as part of the same group

5 - Symmetry (simplicity) - no matter the distance apart, if symmetrical, we perceive as being part of the same group

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Visual Constancy

Perceive an object as being unchanged despite changes in the surrounding environment

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Size Constancy

Perceive that an actual objects size remains the same, even when the object through the retina is changing size

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Shape Constancy

When objects are at different angles, we perceive them as being the same object

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Colour and Brightness Constancy

Tendency to perceive as object as maintaining it’s level of brightness in relation to its surroundings, despite different levels of light coming through the retina

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Perceptual Set and Expectancy

The predisposition/readiness to perceive particular features in a certain way.

Works in two ways; selecting relevant information or interpreting actual information

Not easy to change your perceptual set, audibly and visually and it can be very dangerous

Press-on-itis and get-home-itis can cause problems (747 crash)

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Physiological Limitations of Perception

Vision is not our most reliable sense!!!!

Can often be a mismatch between visual and vestibular system which can lead to illusions and then perceptual errors

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3 Categories of Illusion (most common)

Visual

Auditory

Kinaesthetic

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Visual Illusion of Comparative Size

Pine trees example

When you expect an object to be of a certain size but in reality it may be smaller or larger - separation clearance may be effected

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Visual Illusion of Perspective

When we expect things to be of a certain way or shape, we then perceive them in that way when in reality it could be totally different

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Auto-Kinetic Illusion (Autokinesis)

Night flying with a light in the distance with no visual background, can cause the light to appear as if it is moving.

Caused by the saccades within our eyes.

Danger - people have confused stars as being ac lights or fishing boats being stars

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Taxiing Illusions

Depends on your relative motion to the ground and the heigh above it. Can make you think you are taxing too fast or too slow.

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TakeOff and Missed Approach Illusions

Somatogravic Illusion - feel like you are flying with a steeper angle than you are

Can be fatal (FlyDubai)

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False Horizons

Surface lights or fishing boat lights being confused as stars and causing accidents

Gently Sloped Terrain or Bank of Cloud

If flying visually, you will fly using the gradient of the land (false attitude) putting you into nose down or nose up /side causing you to potentially be higher or lower than you think

RELY ON INSTRUMENTS

Cruise Illusions

Vertical separation

AC coming towards you end up going beneath

Mountain or terrain appears smaller when you get closer to it

Holding Illusions

When you are going round and round and round, can lead to;

Somatogyral Illusion - think you have banked over in the opposite direction when returning S&L

Corioless - Stimulating 1 or more of your vestibular apparatus

Vertigo - Dizziness or tumbling sensation

JUST KEEP YOUR HEAD STILL AND BREATHE

Approach and Landing Lights

PAPIs and VASIs

All red - too low
3 Red - slightly low 
2 R 2 W - Approach character 
3 white - slightly high
4 white - too high

Visual texture flow helps with final height and speed judgement

Landing Visual Aiming Point

Should be looking to touchdown just after the threshold lines (piano keys)

Keep your visual aiming point slightly in front of touchdown point as the AC could bear very long

Keep looking at same point on the approach

Landing Illusion: Visibility

Poor visibility (Haze, fog, cloud) makes the RW seem further away than it actually is

You then think you are too low

Pitch Up

Leads to a too steep approach and possible overshoot

Landing Illusion: Runway Width

Narrower RW

Illusion of being too height
Think you are too high
Pitch down to correct
Leads to a shallow approach and possible undershoot

Wider RW

Illusion of being too low
Think you are too low
Pitch up to correct
Leads to a very steep approach, early roll out/round out/ flare possible

Landing Illusion: Runway Slope

Downward sloping runway

Think you are too low, RW seems longer / bigger
Pitch up to correct
Overshoot, steep approach and early flare possible

RW sloping up

Think you are too high, RW seems shorter / smaller
Pitch down to correct
Undershoot possible

Landing Illusion: Black Hole Effect

Caused by flying at night time over featureless terrain (desert/ocean) with no visual reference Makes you think you are closer to the RW than you are, think that you are too high So you pitch down to correct Which leads to a shallow approach, possible undershoot

Landing Illusion: Rain on Windscreen (angle of approach)

This is possible day and night The rain on the windscreen has a magnifying effect which makes you think you are too high (RW drops beneath you) This makes you pitch down to correct Leads to a low shallow approach with a possible undershoot

Landing Illusion: Rain on windscreen (speed)

In the day: - You think you are further away than you actually are so you think you are flying slower than you actually are - Thrust / power increased to correct - Leads to a possible overspeed/ too higher approach speed In the night: - The RW lights appear brighter which makes you think that the RW is closer than it actually is and that you are approaching too fast - Power/thrust reduced to slow you down - This decreases the speed and could lead to a potential stall

Height Judgement

Over very smooth surfaces with no details, you think you are higher than you are This can cause you to pitch down potentially to a point where you are far too low Could be dangerous for clearance White out can also give us the same illusion (snow)

Mid-Air Collisions

Same relative bearing, travelling at the same speed You perception will not pick up the relative motion which makes it very hard to spot The eye saccades when resting then pick up the AC when it is getting closer, but only in bits. Starts very small but very quickly will be much bigger and closer (DHL and Russian flight)

To Protect yourself From Illusions

Before flight make sure you are planning well, you know what is supposed to be happening, you train well During the flight, make sure you are scanning, checking your instruments and believing your instruments!!!!