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Airplane Flying Handbook
Night Operations
Night Illusions

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Airplane Flying Handbook

Preface

Table of Contents

Chapter 1,Introduction to Flight Training
Chapter 2,Ground Operations
Chapter 3,Basic Flight Maneuvers
Chapter 4, Slow Flight, Stalls, and Spins
Chapter 5, Takeoff and Departure Climbs
Chapter 6, Ground Reference Maneuvers
Chapter 7, Airport Traffic Patterns
Chapter 8, Approaches and Landings
Chapter 9, Performance Maneuvers
Chapter 10, Night Operations
Chapter 11,Transition to Complex Airplanes
Chapter 12, Transition to Multiengine Airplanes
Chapter 13,Transition to Tailwheel Airplanes
Chapter 14, Transition to Turbo-propeller Powered Airplanes
Chapter 15,Transition to Jet Powered Airplanes
Chapter 16,Emergency Procedures

Glossary

Index

After the eyes have adapted to the dark, the entire
process is reversed when entering a lighted room. The
eyes are first dazzled by the brightness, but become
completely adjusted in a very few seconds, thereby losing
their adaptation to the dark. Now, if the dark room
is reentered, the eyes again go through the long process
of adapting to the darkness.

The pilot before and during night flight must consider
the adaptation process of the eyes. First, the eyes
should be allowed to adapt to the low level of light
and then they should be kept adapted. After the eyes
have become adapted to the darkness, the pilot should
avoid exposing them to any bright white light that
will cause temporary blindness and could result in
serious consequences.

Temporary blindness, caused by an unusually bright
light, may result in illusions or after images until the
eyes recover from the brightness. The brain creates
these illusions reported by the eyes. This results in
misjudging or incorrectly identifying objects, such as
mistaking slanted clouds for the horizon or populated
areas for a landing field. Vertigo is experienced as a
feeling of dizziness and imbalance that can create or
increase illusions. The illusions seem very real and
pilots at every level of experience and skill can be
affected. Recognizing that the brain and eyes can play
tricks in this manner is the best protection for flying at
night.

Good eyesight depends upon physical condition.
Fatigue, colds, vitamin deficiency, alcohol, stimulants,
smoking, or medication can seriously impair vision.
Keeping these facts in mind and taking adequate precautions
should safeguard night vision.

In addition to the principles previously discussed, the
following items will aid in increasing night vision
effectiveness.
• Adapt the eyes to darkness prior to flight and
keep them adapted. About 30 minutes is needed
to adjust the eyes to maximum efficiency after
exposure to a bright light.
• If oxygen is available, use it during night flying.
Keep in mind that a significant deterioration in
night vision can occur at cabin altitudes as low as
5,000 feet.
• Close one eye when exposed to bright light to
help avoid the blinding effect.
• Do not wear sunglasses after sunset.
• Move the eyes more slowly than in daylight.
• Blink the eyes if they become blurred.
• Concentrate on seeing objects.
• Force the eyes to view off center.
• Maintain good physical condition.
• Avoid smoking, drinking, and using drugs that
may be harmful.

NIGHT ILLUSIONS

In addition to night vision limitations, pilots should be
aware that night illusions could cause confusion and
concerns during night flying. The following discussion
covers some of the common situations that cause
illusions associated with night flying.

On a clear night, distant stationary lights can be mistaken
for stars or other aircraft. Even the northern
lights can confuse a pilot and indicate a false horizon.
Certain geometrical patterns of ground lights, such as
a freeway, runway, approach, or even lights on a moving
train can cause confusion. Dark nights tend to
eliminate reference to a visual horizon. As a result,
pilots need to rely less on outside references at night
and more on flight and navigation instruments.

Visual autokinesis can occur when a pilot stares at a
single light source for several seconds on a dark night.
The result is that the light will appear to be moving.
The autokinesis effect will not occur if the pilot
expands the visual field. It is a good procedure not to
become fixed on one source of light.

Distractions and problems can result from a flickering
light in the cockpit, anticollision light, strobe lights,
or other aircraft lights and can cause flicker vertigo. If
continuous, the possible physical reactions can be
nausea, dizziness, grogginess, unconsciousness,
headaches, or confusion. The pilot should try to eliminate
any light source causing blinking or flickering
problems in the cockpit.

A black-hole approach occurs when the landing is
made from over water or non-lighted terrain where the
runway lights are the only source of light. Without
peripheral visual cues to help, pilots will have trouble
orientating themselves relative to Earth. The runway
can seem out of position (downsloping or upsloping)
and in the worse case, results in landing short of the
runway. If an electronic glide slope or visual approach
slope indicator (VASI) is available, it should be used.
If navigation aids (NAVAIDs) are unavailable, careful
attention should be given to using the flight instruments
to assist in maintaining orientation and a normal
approach. If at any time the pilot is unsure of his or her
position or attitude, a go-around should be executed.

 

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