Night Operations
Chapter 12
Introduction
It must be understood that fl ying at night presents a number
of new challenges for the pilot and additional equipment for
the aircraft. Flying at night in a weight-shift control (WSC)
aircraft should be done only with some visual reference
to the ground such as city lights or a full moon. Flying
with no consistent visual reference to the surface results in
disorientation, a likely loss of control, and an accident. New
WSC aircraft can be fi tted with instruments similar to those
in airplanes in order to fl y at night without visual reference
to the horizon, but this is not recommended. However, fl ying
with instruments is covered in this chapter.
Aircraft must have position lights
Sport pilots and private pilots with night restriction can fly
Night
Sunset/Sunrise
Civil Twlight
Day
Figure 12-1. Day, twilight, and night time.
Pilot Requirements
Flying at night requires additional pilot skills and a private
pilot certifi cate. It is possible to have a private pilot certifi cate
with a “Night Flight Prohibited” limitation if the pilot did
not complete night fl ight training and is restricted from night
fl ight, similar to that for Sport Pilots. This is an option for
pilots who want a private pilot certifi cate but do not plan to
fl y at night. If the pilot fi rst obtains the private certifi cate
with the night limitation, the limitation can be removed after
completing the private pilot WSC night training. The training
that must be accomplished at night for WSC private pilot
night fl ying privileges is:
1. One cross-country fl ight over 75 nautical miles (NM)
total distance, and
2. Ten takeoffs and landings (each landing involving a
fl ight in the traffi c pattern) at an airport.
Sport pilots or private pilots with the night limitation are not
allowed to fl y at night; however, they can fl y after sunset
during civil twilight until night if the aircraft is properly
equipped with position lights. Civil twilight is when the sun
is less than 6° below the horizon, about 30 minutes before
sunrise or after sunset, and varies by latitude throughout
the year. It is the time when there is enough light outdoors
for activities to be conducted without additional lighting.
[Figure 12-1] If it is overcast and visibility is inadequate,
good pilot judgment would dictate not to fl y after sunset.
Equipment and Lighting
Title 14 of the Code of Federal Regulations (14 CFR) part 91
specifi es the minimum aircraft equipment required for fl ight
during civil twilight and night fl ight. This equipment includes
only position lights. Normal standard category aircraft are
required to have this additional equipment as would also be
recommended for WSC night fl ight, including anti-collision
light, landing lights, adequate electrical source for lights, and
spare fuses. The standard instruments required for instrument
fl ight under 14 CFR part 91 are a valuable asset for aircraft
control at night but are not required.
Aircraft position lights are required on all aircraft from sunset
to sunrise in an arrangement similar to those on boats and
ships. A red light is positioned on the left wing tip, a green
light on the right wing tip, and a white light on the tail.
[Figures 12-2 and 12-3] This arrangement allows the pilot
to determine the general direction of movement of other
aircraft in fl ight. If both position lights of another aircraft
are observed, a red light on the right and a green light on the
left, the aircraft is fl ying toward the pilot and could be on a
collision course. Similarly, a green light on the right and a
red light on the left indicate the aircraft is fl ying in the same
direction as the pilot observing the lights. Landing lights
are not only useful for taxi, takeoffs, and landings, but also
provide an additional means by which aircraft can be seen
at night by other pilots. [Figure 12-4]
The Federal Aviation Administration (FAA) has initiated
a voluntary pilot safety program called “Operation Lights
On.” The “lights on” idea is to enhance the “see and be seen”
concept of averting collisions in the air and on the ground and
to reduce the potential for bird strikes. Pilots are encouraged
to turn on their landing lights when operating within 10 miles
of an airport. This is for both day and night or in conditions
of reduced visibility. This should also be done in areas where
fl ocks of birds may be expected.
Although turning on aircraft lights supports the “see and be
seen” concept, pilots should not become complacent about
keeping a sharp lookout for other aircraft. Most aircraft lights
blend in with stars or city lights at night and go unnoticed
Figure 12-2. Position lights.
Figure 12-3. Modern LED position lights on carriage wheel pants
simplify the installation with no wires running from the carriage
to the wing tips.
Figure 12-4. Landing light on WSC aircraft taxiing at night.
At least one reliable fl ashlight is recommended as standard
equipment on all night fl ights. Remember to place a spare
set of batteries in the fl ight kit. A spare fl ashlight is the better
choice, eliminating the need to change batteries during fl ight.
unless a conscious effort is made to distinguish them from
other lights.
Pilot Equipment
Before beginning a night fl ight, carefully consider personal
equipment that should be readily available during the fl ight.
Figure 12-5. WSC aircraft equipped for night cross-country flight with flashlight and aeronautical charts on kneeboards.
A D-cell size fl ashlight with a bulb switching mechanism that
can be used for white or red light is preferable. The white light
is used while performing the prefl ight visual inspection on
the ground, and the red light is used when performing fl ight
deck operations. Since the red light is nonglaring, it does not
impair night vision. Some pilots prefer two fl ashlights, one
with a white light for prefl ight and the other a penlight with
a red light. The latter can be suspended by a string around
the neck to ensure the light is always readily available. Be
aware that if a red light is used for reading an aeronautical
chart, the red features of the chart will not show up.
Aeronautical charts are essential for night cross-country fl ight
and, if the intended course is near the edge of the chart, the
adjacent chart should also be available. The lights of cities
and towns can be seen at surprising distances at night, and if
this adjacent chart is not available to identify those landmarks,
confusion could result. Regardless of the equipment used,
organization of the fl ight deck eases the burden on the pilot
and enhances safety. [Figure 12-5]
Airport and Navigation Lighting Aids
The lighting systems used for airports, runways, obstructions,
and other visual aids at night are other important aspects of
night fl ying.
Lighted airports located away from congested areas can be
identifi ed readily at night by the lights outlining the runways.
Airports located near or within large cities are often diffi cult
to identify in the maze of lights. It is important to know the
exact location of an airport relative to the city, and also be
able to identify these airports by the characteristics of their
lighting pattern.
Aeronautical lights are designed and installed in a variety
of colors and confi gurations, each having its own purpose.
Although some lights are used only during low ceiling and
visibility conditions, this discussion includes only the lights
that are fundamental to visual flight rules (VFR) night
operation.
It is recommended that prior to a night fl ight, and particularly
a cross-country night fl ight, the pilot check the availability
and status of lighting systems at the destination airport. This
information can be found on aeronautical charts and in the
Airport/Facility Directory (A/FD). The status of each facility
can be determined by reviewing pertinent Notices to Airmen
(NOTAMs).
A rotating beacon is used to indicate the location of most
airports. The beacon rotates at a constant speed, thus
producing what appears to be a series of light fl ashes at
regular intervals. These fl ashes may be one or two different
colors that are used to identify various types of landing areas.
For example:
• Lighted civilian land airports—alternating white and
green
• Lighted civilian water airports—alternating white and
yellow
• Lighted military airports—alternating white and
green, but are differentiated from civil airports by
dual peaked (two quick) white fl ashes, then green
Beacons producing red fl ashes indicate obstructions or areas
considered hazardous to aerial navigation. Steady burning
red lights are used to mark obstructions on or near airports
and sometimes to supplement fl ashing lights on en route
obstructions. High intensity fl ashing white lights are used to
mark some supporting structures of overhead transmission
lines that stretch across rivers, chasms, and gorges. These
high intensity lights are also used to identify tall structures,
such as chimneys and towers.
As a result of technological advancements in aviation,
runway lighting systems have become quite sophisticated
to accommodate takeoffs and landings in various weather
conditions. However, the pilot whose fl ying is limited to VFR
needs to be concerned only with the following basic lighting
of runways and taxiways.
The basic runway lighting system consists of two straight
parallel lines of runway-edge lights defi ning the lateral limits of
the runway. These lights are aviation white, although aviation
yellow may be substituted for a distance of 2,000 feet from
the far end of the runway to indicate a caution zone. At some
airports, the intensity of the runway-edge lights can be adjusted
to satisfy the individual needs of the pilot. The length limits
of the runway are defi ned by straight lines of lights across the
runway ends. At some airports, the runway threshold lights are
aviation green, and the runway end lights are aviation red.
At many airports, the taxiways are also lighted. A taxiway-
edge lighting system consists of blue lights that outline
the usable limits of taxi paths. See the Pilot’s Handbook
of Aeronautical Knowledge for additional information on
airport lighting.
Night Vision
Generally, most pilots are poorly informed about night vision.
Human eyes never function as effectively at night as the eyes
of nocturnal animals, but if humans learn how to use their
eyes correctly and know their limitations, night vision can
be improved signifi cantly. The human eye is constructed so
that day vision is different from night vision. Therefore, it is
important to understand the eye’s construction and how the
eye is affected by darkness.
Innumerable light-sensitive nerves called cones and rods are
located at the back of the eye or retina, a layer upon which all
images are focused. These nerves connect to the cells of the
optic nerve, which transmits messages directly to the brain.
The cones are located in the center of the retina, and the rods
are concentrated in a ring around the cones. [Figure 12-6]
The function of the cones is to detect color, details, and
faraway objects. The rods function when something is seen
out of the corner of the eye or peripheral vision. They detect
objects, particularly those that are moving, but do not give
detail or color—only shades of gray. Both the cones and the
rods are used for vision during daylight.
Although there is not a clear-cut division of function, the rods
make night vision possible. The rods and cones function in
daylight and in moonlight; in the absence of normal light,
the process of night vision is almost entirely a function of
the rods.
The fact that the rods are distributed in a band around the
cones and do not lie directly behind the pupils makes off-
center viewing (looking to one side of an object) important
during night fl ight. During daylight, an object can be seen
best by looking directly at it, but at night a scanning procedure
to permit off-center viewing of the object is more effective.
Therefore, the pilot should consciously practice this scanning
procedure to improve night vision.
The eye’s adaptation to darkness is another important aspect
of night vision. When a dark room is entered, it is diffi cult to
see anything until the eyes become adjusted to the darkness.
In the adaptation process, the pupils of the eyes fi rst enlarge
to receive as much of the available light as possible. After
approximately 5 to 10 minutes, the cones become adjusted to
the dim light and the eyes become 100 times more sensitive
to light than they were before the dark room was entered.
About 30 minutes is needed for the rods to become adjusted
to darkness; when they do adjust, they are about 100,000
times more sensitive to light than in the lighted area. After
the adaptation process is complete, much more can be seen,
especially if the eyes are used correctly.
Figure 12-6. Rods and cones.
The rods and
cones (film) of
the retina are
the receptors
which record
the image and
transmit it
through the
optic nerve to
the brain for
interpretation.
Rods and
Cones
Fovea
(All Cones)
Cones active
Area of best day vision
Rods active
Night blind spot
Area of best
night vision
Lens
Retina
Optic nerve
Iris
The pupil (aperture) is the opening at
the center of the iris. The size of the
pupil is adjusted to control the amount
of light entering the eye.
Pupil
Light passes through the cornea (the
transparent window on the front of the
eye) and then through the lens to
focus on the retina.
Cornea
Rod concentration
After the eyes have adapted to the dark, the entire process
is reversed when entering a lighted room. The eyes are fi rst
dazzled by the brightness, but become completely adjusted
in a 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.
Before and during night fl ight, the pilot must consider the
adaptation process of the eyes. First, the eyes should be
allowed to adapt to the low level of light. Then, the pilot
should avoid exposing them to any bright white light that
would cause temporary blindness and possibly result in
serious consequences.
Temporary blindness, caused by an unusually bright light,
may result in illusions or afterimages 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 a populated area for a landing fi eld. 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 fl ying at night.
Good eyesight depends upon physical condition. Fatigue,
colds, vitamin defi ciency, alcohol, stimulants, smoking, or
medication can seriously impair vision. Keeping these facts
in mind and taking appropriate precautions should help
safeguard night vision.
Figure 12-7. At night, the horizon may be hard to discern due to dark
terrain and misleading light patterns on the ground.
In addition to the principles previously discussed, the following
actions aid in increasing night vision effectiveness:
• Adapt the eyes to darkness prior to fl ight, and keep
them adapted. About 30 minutes is needed to adjust
the eyes to maximum effi ciency after exposure to a
bright light.
• Use oxygen during night fl ying, if available. Keep in
mind that a signifi cant deterioration in night vision
can occur at altitudes as low as 5,000 feet.
• Close one eye when exposed to bright light to help
avoid the blinding effect.
• Avoid wearing sunglasses after sunset.
• Move the eyes more slowly than in daylight.
• Blink the eyes if vision becomes 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.
Unique WSC Flight Characteristics
If the WSC aircraft is trimmed properly and the pilot is
profi cient in the basic fl ight maneuvers of climbs, cruise,
and descent procedures, the WSC aircraft speed is easily
determined with control bar pressure and position for normal
fl ight conditions. A pilot can also determine basic climbs and
descents through the feel of the aircraft with the airspeed and
throttle positions. Therefore, basic pitch control can be done
by a profi cient pilot with his or her eyes closed.
As discussed in Chapter 2, Aerodynamics, WSC aircraft
are generally not designed to be roll stable, and any engine
turning effect or movement of the air can put the WSC aircraft
into a roll, which it maintains unless corrected by the pilot.
In other words, releasing the control bar in a WSC aircraft
will not level a bank back to straight fl ight. The pilot must
continually provide input to fl y a constant heading even if this
control is small corrections. In other words, the pilot cannot
level the wings or fl y a straight heading for very long with
his or her eyes closed.
To maintain a constant heading or ground track, one of
three instruments can be used: magnetic compass, global
positioning system (GPS), and aircraft heading indicator.
Without a visual reference, these can be used to fl y straight.
An attitude indicator can be used on WSC aircraft providing
additional instrument reference. These instruments and others
are discussed later in this chapter.
Night Illusions
In addition to night vision limitations, pilots should be aware
that night illusions could cause confusion and concerns
during night fl ying. The following discussion covers some
of the common situations that cause illusions associated with
night fl ying.
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 fl ying
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. [Figure 12-7]
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 fl ight 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 appears to be moving. The autokinesis effect
does not occur if the pilot expands the visual fi eld. It is a
good procedure to vary visual focus and not become fi xed
on one source of light.