Airplane Flying Handbook (FAA-H-8083-3C)
Chapter 11: Night Operations
Introduction
The mechanical operation of an airplane at night is no different than operating the same airplane during the day. The airplane does not
know if it is being operated in the dark or in bright sunlight. It performs and responds to control inputs by the pilot. The
pilot, however, is affected by various aspects of night operations and should take them into consideration during night flight
operations. Some are actual physical limitations affecting all pilots. Others, such as equipment requirements, procedures, and
emergency situations, should also be considered.
According to 14 CFR part 1, section 1.1, Definitions and Abbreviations, “night” means the time between the end of evening civil
twilight and the beginning of morning civil twilight, as published in the Air Almanac, converted to local time. To explain further, the
National Weather Service defines evening civil twilight as the time that begins in the morning, or ends in the evening, when the
geometric center of the sun is 6 degrees below the horizon. Therefore, morning civil twilight begins when the geometric center of the
sun is 6 degrees below the horizon, and ends at sunrise. Evening civil twilight begins at sunset and ends when the geometric center of
the sun is 6 degrees below the horizon. The FAA has an online tool to calculate sunrise, sunset, and civil twilight for any given
location.
For 14 CFR part 61, section 61.57(b)(1) night operations that meet recent flight experience requirements, the term “night” refers to
the time period beginning 1 hour after sunset and ending 1 hour before sunrise. The same regulation requires that during those hours,
no person may act as pilot-in-command (PIC) of an aircraft carrying passengers unless within the preceding 90 days and during those
specified hours, that person has made 3 takeoffs and landings to a full stop. 14 CFR part 61, sections 61.57(b)(1)(i) and (ii) require the
pilot to have made the required takeoffs and landings acting as the sole manipulator of the controls, and to have performed the
takeoffs and landings in an aircraft of the same category, class, and type (if a type rating is required). Other conditions apply if using a
full flight simulator to meet the requirement as described in 14 CFR part 61 (section 61.57(b)(2)) or if seeking to use another
alternative provided in the regulation.
Night flying operations should not be encouraged or attempted except by certificated pilots with knowledge of and experience in
the topics discussed in this chapter.
Night Vision
Due to the physiology of the eye [Figure 11-1], humans experience diminished vision in low-light conditions. Because vision
involves the eyes and brain working together, understanding eye function leads to pilot behaviors that can improve night vision
significantly.
Anatomy of the Eye
⦁ Light from an object enters the eye through the cornea and then continues through the pupil.
⦁ The opening (dilation) and closing (constriction) of the pupil is controlled by the iris, which is the colored
part of the eye. The function of the pupil is similar to that of the diaphragm of a photographic camera: to
control the amount of light.
⦁ The lens is located behind the pupil and its function is to focus light on the surface of the retina.
⦁ The retina is the inner layer of the eyeball that contains photosensitive cells called rods and cones. The
function of the retina is similar to that of the film in a photographic camera: to record an image.
⦁ The cones are located in higher concentrations than rods in the central area of the retina known as the
macula, which measures about 4.5 mm in diameter. The exact center of the macula has a very small
depression called the fovea, which contains cones only. The cones are used for day or high-intensity light
vision. They are involved with central vision to detect detail, perceive color, and identify far-away objects.
⦁ The rods are located mainly in the periphery of the retina—an area that is about 10,000 times more
sensitive to light than the fovea. Rods are used for low light intensity or night vision and are involved with
peripheral vision to detect position references, including objects (fixed and moving) in shades of gray, but
cannot be used to detect detail or to perceive color.
⦁ 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, but in the absence of normal light, the process of night vision
is placed almost entirely on the rods.
⦁ Light energy (an image) enters the eyes and is transformed by the cones and rods into electrical signals that
are carried by the optic nerve to the posterior area of the brain (occipital lobes). This part of the brain
interprets the electrical signals and creates a mental image of the actual object that was seen by the person.
Figure 11-1. Rods and cones.
Types of Vision
Photopic Vision. During daytime or high-intensity artificial illumination conditions, the eyes rely on central vision (foveal cones) to
perceive and interpret sharp images and color of objects. [Figure 11-2]
Figure 11-2. Central Vision.
Mesopic Vision . Occurs at dawn, dusk, or under full moonlight levels and is characterized by decreasing visual acuity and color
vision. Under these conditions, a combination of central (foveal cones) and peripheral (rods)vision is required to maintain appropriate
visual performance.
Scotopic Vision. During nighttime, partial moonlight, or low intensity artificial illumination conditions, central vision (foveal cones)
becomes ineffective to maintain visual acuity and color perception. Under these conditions, if looking directly at an object for more
than a few seconds, the image of the object fades away completely (night blind spot). Peripheral vision (off center scanning) provides
the only means of seeing very dim objects in the dark.
Night Blind Spot
The “Night Blind Spot” appears under conditions of low ambient illumination due to the absence of rods in the fovea. [Figure 11-3]
This absence of rods affects the central 5 to 10 degrees of the visual field. If an object is viewed directly at night, it may go
undetected or it may fade away after initial detection. The night blind spot can hide larger objects as the distance between the pilot
and an object increases.
Figure 11-3. The night blind spot.
Vision Under Dim and Bright Illumination
The eye’s adaptation to darkness is another important aspect of night vision. When a dark room is entered, it is difficult to see
anything until the eyes become adjusted to the darkness. Almost everyone experiences this when entering a darkened movie theater.
In darkness, vision gradually becomes more sensitive to light. Maximum dark adaptation can take up to 30 minutes. Exposure to
aircraft anti-collision lights does not impair night vision adaptation because the intermittent flashes have a very short duration (less
than 1 second). However, if dark-adapted eyes are exposed to a bright light source (searchlights, landing lights, flares, etc.) for a
period of 1 second or more, night vision is temporarily impaired. If it is safe to do so, pilots may close one eye when bright exposure
begins in order to preserve dark adaptation for that eye.
Factors Affecting Vision
⦁ During the day, identification of objects at a distance is aided by good resolution. At night, the
identification range of dim objects is limited and the detail resolution is poor.
⦁ Surface references or the horizon may become obscured by smoke, fog, smog, haze, dust, ice particles,
or other phenomena, even when visibility meets Visual Flight Rule (VFR) minimums. This is especially true
at airports located adjacent to large bodies of water or sparsely populated areas where few, if any, surface
references are available. Lack of horizon or surface reference is common on over-water flights, at night,
and in low-visibility conditions.
⦁ Presence of uncorrected refractive eye disorders such as myopia (nearsightedness–impaired focusing of
distant objects), hyperopia (farsightedness–impaired focusing of near objects), astigmatism (impaired
focusing of objects in different meridians), or presbyopia (impaired focusing of near objects) affect day
and night vision.
⦁ Self-imposed stresses such as self-medication, alcohol consumption (including hangover effects), tobacco
use (including withdrawal), hypoglycemia, sleep deprivation/fatigue, and extreme emotional upset can
seriously impair vision.
⦁ Inflight exposure to low barometric pressure without the use of supplemental oxygen (above 10,000 feet
during the day and above 5,000 feet at night) can result in hypoxia, which impairs visual performance.
⦁ Due to the effects of carbon monoxide on the blood, smokers may experience a physiological altitude that
is much higher than actual altitude. The smoker is thus more susceptible to hypoxia at lower altitudes than
the nonsmoker.
⦁ Other factors that may have an adverse effect on visual performance include windscreen haze, improper
illumination of the flight deck and/or instruments, scratched and/or dirty instrumentation, use of flight deck
red lighting, inadequate flight deck environmental control (temperature and humidity), inappropriate
sunglasses and/or prescription glasses/contact lenses, and sustained visual workload during flight. Red light
illumination distorts colors (magenta and yellow pigments both appear as red, and cyan pigment appears
black) on aeronautical charts. Pilots should use it only where optimum outside night vision capability is
necessary. Dim white flight deck lighting should be available when needed for map and instrument reading.
⦁ Monovision contact lenses (one contact lens for distant vision and the other lens for near vision) make the
pilot alternate his/her vision; that is, a person uses one eye at a time, suppressing the other, and
consequently impairs binocular vision and depth perception. The FAA recommends not using these lenses
when piloting an aircraft..
⦁ A flickering light in the flight deck, anti-collision lights, or other aircraft lights, may cause interference
with brain function. Although rare, this may occur at a frequencies from 1 to 20 hertz. If continuous, the
possible physical reactions can be nausea, dizziness, grogginess, unconsciousness, headaches, or confusion.
Pilots should try to eliminate or screen out any light source that might cause an unwanted reaction to
blinking or flickering lights.
⦁ Sunglasses can aid the dark adaptation process, which is delayed by prolonged exposure to bright sunlight.
Night Illusions
Visual illusions are especially hazardous because pilots rely on their eyes for correct information. Darkness or low visibility increases
pilot susceptibility to error. Two illusions that lead to spatial disorientation, false horizon and autokinesis, concern the visual system
only.
False Horizon
Flying at night under clear skies with ground lights below can result in situations where it is difficult to distinguish the ground lights
from the stars. A dark scene spread with ground lights and stars, and certain geometric patterns of ground lights can provide
inaccurate visual information, making it difficult to align the aircraft correctly with the actual horizon. An aurora borealis display at
night or a visible sloping cloud formation can also affect a pilot's sense of the horizon. A similar problem is encountered during
certain daylight operations over large bodies of water. Various atmospheric and water conditions can create a visual scene without a
discernible horizon.
Autokinesis
In the dark, a stationary light will appear to move about when stared at for many seconds. The disoriented pilot could lose control of
the aircraft in attempting to align it with the false movements of this light.
Featureless Terrain Illusion
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, orientation is difficult. The runway can seem out of position (down-sloping or
up-sloping) and in the worst 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, the flight instruments assist in maintaining
orientation and a normal approach. Anytime position in relation to the runway or altitude is in doubt, the pilot should execute a go-
around.
Bright runway and approach lighting systems, especially where few lights illuminate the surrounding terrain, may create the illusion
of being lower or having less distance to the runway. In this situation, the tendency is to fly a higher approach. Also, flying over
terrain with only a few lights makes the runway recede or appear farther away. With this situation, the tendency is to fly a lower-than-
normal approach. If the runway has a city in the distance on higher terrain, the tendency is to fly a lower-than-normal approach. A
good review of the airfield layout and boundaries before initiating any approach helps maintain a safe approach angle.
Ground Lighting Illusions
Lights along a straight path, such as a road or lights on moving trains, can be mistaken for runway and approach lights. Bright runway
and approach lighting systems, especially where few lights illuminate the surrounding terrain, may create the illusion of less distance
to the runway. The pilot who does not recognize this illusion will often fly a higher approach.
Illusions created by runway lights result in a variety of problems. Bright lights or bold colors advance the runway, making it appear
closer. Night landings are further complicated by the difficulty of judging distance and the possibility of confusing approach and
runway lights. For example, when a double row of approach lights joins the boundary lights of the runway, there can be confusion as
to where the approach lights terminate and runway lights begin. Under certain conditions, approach lights can make the aircraft seem
higher in a turn to final, than when its wings are level.
Pilot Equipment
As part of preflight preparation, pilots should carefully consider the personal equipment that should be readily available during the
flight to include a flashlight, aeronautical charts, pertinent data for the flight, and a flight deck checklist containing procedures for the
following tasks:
1. Before starting engines
2. Before takeoff
3. Cruise
4. Before landing
5. After lan ding
6. Stopping en gines
7. Emergencies
At least one reliable flashlight is recommended as standard equipment on all night flights. A reliable incandescent or light-emitting
diode (LED) dimmable flashlight able to produce white/red light is preferable. The flashlight should be large enough to be easily
located in the event it is needed. It is also recommended to have a spare set of batteries for the flashlight readily available. The white
light is used while performing the preflight visual inspection of the airplane, the red light is used when performing flight deck
operations, and the dim white light may be used for chart reading. Many charts can be displayed on a EFB, which does not require a
flashlight. However, its brightness should be set so as not to seriously impair night vision.
Since the red light is non-glaring, it will not impair night vision. Some pilots prefer two flashlights, one with a white light for preflight
and the other a penlight type with a red light. The latter can be suspended by a string from around the neck to ensure the light is
always readily available. As mentioned earlier, red light distorts color perception of pigments other than red on charts.
Aeronautical charts are essential for night cross-country flight 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 flight deck
eases the burden and enhances safety. Organize equipment and charts and place them within easy reach prior to taxiing.
Airplane Equipment and Lighting
14 CFR part 91, section 91.205(c) specifies the basic minimum airplane equipment that is required for VFR flight at night. This
equipment includes basic instruments, lights, electrical energy source, and spare fuses if applicable.
The standard instruments required by 14 CFR part 91, section 91.205(d) for IFR flight are valuable assets for aircraft control at night.
14 CFR part 91, section 91.205(c)(3) specifies that during VFR flight at night, operating aircraft are required to have an approved
anti-collision light system, which can include a flashing or rotating beacon and position lights. However, 14 CFR part 91, section
91.209(b) gives the pilot-in-command leeway to turn off the anti-collision lights in the interest of safety. Airplane position lights are
arranged similar to those of boats and ships. A red light is positioned on the left wingtip, a green light on the right wingtip, and a
white light on the tail. [Figure 11-4]
Figure 11-4. Position lights.
This arrangement provides a means to determine the general direction of movement of other airplanes in flight. If both a red and
green light of another aircraft are observed, and the red light is on the left and the green to the right, the airplane is flying the same
direction. Care must be taken to maintain clearance. If red were on the right and green to the left, the airplane could be on a collision
course.
Landing lights are not only useful for taxi, takeoffs, and landings, but also provide a means by which airplanes can be seen at night by
other pilots. Pilots are encouraged to turn on their landing lights when operating within 10 miles of an airport and below 10,000 feet.
Operation with landing lights on applies to both day and night or in conditions of reduced visibility. This should also be done in areas
where flocks of birds may be expected.
Although turning on aircraft lights supports the “see and be seen” concept, pilots should continue to keep a sharp lookout for other
aircraft. Aircraft lights may blend in with the stars or the lights of the cities at night and go unnoticed unless a conscious effort is
made to distinguish them from other lights.
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 flying.
Lighted airports located away from congested areas are identified readily at night by the lights outlining the runways. Airports located
near or within large cities are often difficult to identify as the airport lights tend to blend with the city lights. It is important to not only
know the exact location of an airport relative to the city, but also to be able to identify these airports by the characteristics of their
lighting patterns.
Aeronautical lights are designed and installed in a variety of colors and configurations, 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 flight, and particularly a cross-country night flight, that a check of the availability and status of
lighting systems at the destination airport is made. This information can be found on aeronautical charts and in the Chart
Supplements. The status of each facility can be determined by reviewing pertinent Notices to Airmen (NOTAMs).
Most airports have rotating beacons. The beacon rotates at a constant speed, thus producing a series of light flashes at regular
intervals. These flashes may consist of a white flash and 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 lights
⦁ Lighted civilian water airports—alternating white and yellow lights
⦁ Lighted m ilitary airports—alternating white and green lights, but are differentiated from civil airports by
dual peaked (two quick) white flashes, then green
Beacons producing red flashes 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 flashing lights on en route obstructions. High-intensity,
flashing 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, runway lighting systems have become quite sophisticated to accommodate takeoffs and
landings in various weather conditions. However, if flying is limited to VFR only, it is important to be familiar with the basic lighting
of runways and taxiways.
The basic runway lighting system consists of two straight parallel lines of runway edge lights defining 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 activated and adjusted by radio
control. The control system consists of a 3-step control responsive to 7, 5, and/or 3 microphone clicks. This 3-step control turns on
lighting facilities capable of either 3-step, 2-step, or 1-step operation. The 3-step and 2-step lighting facilities can be altered in
intensity, while the 1-step cannot. All lighting is illuminated for a period of 15 minutes from the most recent time of activation and
may not be extinguished prior to end of the 15-minute period. Suggested use is to always initially key the mike 7 times; this assures
that all controlled lights are turned on to the maximum available intensity. If desired, adjustment can then be made, where the
capability is provided, to a lower intensity by keying 5 and/or 3 times. Due to the close proximity of airports using the sam e
frequency, radio-controlled lighting receivers may be set at a low sensitivity requiring the aircraft to be relatively close to activate the
system. Consequently, even when lights are on, the pilot should always key the mike as directed when overflying an airport of
intended landing or just prior to entering the final segment of an approach. This assures the aircraft is close enough to activate the
system and a full 15-minute lighting duration is available.
The length limits of the runway are defined 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.
Training for Night Flight
Learning to fly safely at night takes time and experience. Pilot’s should practice maneuvers at night including straight-and-level flight,
climbs and descents, level turns, climbing and descending turns, and steep turns. Practicing recovery from unusual attitudes should
only be done with a flight instructor. Pilots may practice these maneuvers with all the flight deck lights turned OFF, as well as ON.
This blackout training simulates an electrical or instrument light failure. Pilots should also use the navigation equipment and local
NAVAIDs during the training. In spite of fewer references or checkpoints, night cross-country flights do not present particular
problems if pre-planning is adequate. Just as during the day, the pilot continuously monitors position, time estimates, fuel consumed,
and uses NAVAIDs, if available, to assist in monitoring en route progress.
Preparation and Preflight
Night flying requires that pilots are aware of, and operate within, their abilities and limitations. Although careful planning of any
flight is essential, night flying demands more attention to the details of preflight preparation and planning.
Preparation for a night flight includes a thorough review of the available weather reports and forecasts with particular attention given
to temperature/dew point spread. A narrow temperature/dew point spread may indicate the possibility of fog. Emphasis should also be
placed on wind direction and speed, since its effect on the airplane cannot be as easily detected at night as during the day.