Transcript OGHFA Operator’s Guide to Human Factors in Aviation Human Performance & Limitations Understanding Visual Illusions And Disorientation Page 1 1.HP_09_Vision and Illusions.

OGHFA
Operator’s Guide to
Human Factors in Aviation
Human Performance &
Limitations
Understanding Visual Illusions
And Disorientation
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1.HP_09_Vision and Illusions
OGHFA
Operator’s Guide to
Human Factors in Aviation
Human Performance
Understanding Visual Illusions and Disorientation
1. Introduction
2. Visual illusions
3. Turning illusions
4. False climb illusions
5. Preventing spatial disorientation
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Disorientation and illusions - Introduction

Human senses

Visual illusions

Disorientation
Turns
Pitch

How to avoid / minimise

How to recover
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Human Senses - Orientation and Balance
 Eyes
Horizontal and Vertical
Distance and Height
Movement
 Inner Ear (vestibular)
Rate
Rotation
 Tactile (motion or position)
Acceleration
Feel
Force
They work together
Gravity
but
They are all a source of error
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Visual Illusions
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Visual Illusion - False Horizon
Rely on the flight instruments,
never on your perception;
ignore your internal instruments
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Visual Illusion
Copyright Martin Aves
‘Black Hole’ Approach
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Visual Illusion - An Incident
FAF 5 DME
3800 ft
Modern ‘Heavy’ EFIS / FMS equipped aircraft (VNAV)
VOR/DME, (Non-Precision Approach), Night VFR
VOR / DME
MDA 339 ft
TERRAIN PULL UP
250 ft agl, 124 ft aal
1.5 nm
300 ft/min
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Visual Illusion - ‘Black Hole’ Visual approach
A long, straight-in approach
Up sloping terrain before a runway
An airport located on the near side of a small city,
with an irregular matrix of lights spread over
hillsides behind the airport.
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Visual Illusions - ‘Black Hole’ Visual Approach
Check altitude against range
Monitor vertical speed
Use all navigation aids
Beware of night visual
approaches
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Visual Illusion - runway perspective
Low
High
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An Incident – up sloping, long, narrow
runway; down slope terrain
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An Incident – up sloping, long, narrow
runway; down slope terrain
Beware of night visual approaches
Check QNH (altimeter setting)
Always Pull Up for EGPWS warnings
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Turning illusions
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Turning Illusion - Leans (slow roll rate, steady turn)
Rely on the flight instruments never on your perception
Ignore your internal instruments
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Turning Illusion Coriolis (steady turn, head movement)
An almost unbearable sensation that the aircraft is
rolling, pitching, and yawing all at the same time
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Turning illusion (long turn, then roll exit)
i.e.. banking during holding pattern
After approx 30 seconds, the brain has no
sense of turning any more.
If the pilot perceives a turn in the opposite
direction, he may bank to re-enter the
original turn and overbank to compensate.
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Turning illusion (long turn, then roll exit)
The aircraft makes a
sustained turn
After approx 30 seconds, the brain has no
more sense of turning
The pilot thinks the
aircraft is wings level
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Turning illusion (long turn, then roll exit)
If the aircraft is now straightened, the brain
senses a turn in the opposite direction.
The pilot thinks the
aircraft is turning in the
opposite direction.
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Turning illusions - Defenses
Rely on the flight instruments never on your perception
Ignore your internal instruments
If your orientation is disturbed – look at and concentrate on a nearby
fixed point on the instrument panel. Check the aircraft roll attitude.
Sustained turns can be perceived as level flight or a false turn.
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False Climb illusion
The pilot thinks the aircraft is climbing, but the aircraft pitch
attitude is level or at a lower attitude than perceived.
Vertical as sensed by
gravity
False vertical cues due
to acceleration; give
apparent climb
Acceleration
Gravity (1g)
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False Climb illusion (during acceleration)
During accelerations the pilot thinks the
aircraft is climbing, but the aircraft pitch
attitude is at a lower attitude than sensed.
Acceleration leads to
false climb attitude
Acceleration
Avoid the tendency to push forward.
Concentrate on pitch attitude.
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False Climb illusion - Takeoff and Go Around
Accelerating from 170 to 200 knots over 10 seconds
•
•
+ 0.16g longitudinal acceleration
~ 9 degrees ‘nose up’ attitude change
Use the INSTRUMENTS, follow SOPs
Do not push the nose down
Rely on the flight instruments never on your perception
Ignore your internal instruments
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False Attitude Illusion on Approach Deceleration
Deceleration due to lowering the flaps or use of airbrake is perceived as a
nose-down sensation
On the runway, before the nose wheel touches down, the deceleration from
spoilers may be perceived falsely as a too-low pitch attitude.
False attitude due to deceleration; gives
apparent nose down pitch
Vertical as sensed by
gravity
Deceleration
Gravity (1g)
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Simulators Cannot Imitate All Illusions
Simulators can provoke some illusions:
but ‘g’ never exceeds 1g
Simulators cannot imitate the false climb illusion
Simulators have tilt, but no acceleration.
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Prevent / Recover from Disorientation
 Believe the instruments, regardless of your sensation
 Don't trust your senses, particularly in low-visibility conditions
 In moments of stress, base decisions on the instruments; don’t use
your ‘instinct’ or feelings
Human senses can be confused and
degrade without warning
Aircraft sensors and displays are more reliable than humans
Aircraft sensors and displays have built-in warning and alerting
systems; humans do not
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Preventing Spatial Disorientation
Confidence and currency in your instrument flying
Use an instrument scan - practice
Prioritize workload
Golden Rule #1: First fly the aircraft
Experience
Practice go-arounds
Always cross-check instruments when visual,
and especially with autopilot engaged
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Scan your flight instruments
Scan all
instruments and
believe them
Your mental attitude
controls your
‘attitude’.
Do not make control
inputs based on your
‘feelings’.
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Disorientation and Illusion
Believe your flight
instruments