Night Operations Lesson by wifiCFI
Night Operations (AFH C10)
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 bright sunlight. It performs and responds to control inputs by the pilot.
The pilot, however, is affected by various aspects of night operations and must take them into consideration during night flight operations.
Some are actual physical limitations affecting all pilots while others, such as equipment requirements, procedures, and emergency situations, must also be considered.
Generally, most pilots are poorly informed about night vision.
Human eyes never function as effectively at night as the eyes of animals with nocturnal habits, but if humans learn how to use their eyes correctly and know their limitations, night vision can be improved significantly.
The brain and eyes act as a team for a person to see well; both must be used effectively.
Due to the physiology of the eye, limitations on sight are experienced in low light conditions, such as at night.
To see at night, the eyes are used differently than during the day.
Therefore, it is important to understand the eye’s construction and how the eye is affected by darkness.
Anatomy of the Human Eye:
The cones are located in the center of the retina.
The function of the cones is to detect color, details, and faraway objects.
Best for center object viewing.
Both the cones and the rods are used for daytime vision.
The rods are concentrated in a ring around the cones.
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.
The rods make night vision possible.
The Night Blind Spot
At night there is a blind spot in the center of the field of vision, the night blind spot.
If an object is in this area, it may not be seen.
The size of this blind spot increases as the distance between the eye and the object increases.
Therefore, the night blind spot can hide larger objects as the distance between the pilot and an object increases.
Use of a scanning procedure to permit off-center viewing of the object is more effective.
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 difficult to see anything until the eyes become adjusted to the darkness.
Almost everyone experiences this when entering a darkened movie theater.
In this process, the pupils of the eyes 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 approximately 100 times more sensitive to the light than they were before the dark room was entered.
Much more time, about 30 minutes, is needed for the rods to become adjusted to darkness, but when they do adjust, they are about 100,000 times more sensitive to light than they were in the lighted area.
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 re-entered, the eyes again go through the long process of adapting to the darkness.
Before and during night flight, the adaptation process of the eyes must be considered.
First, adapt to the low level of light and then stay adapted.
After the eyes are adapted to the darkness, avoid exposing them for more than one second to any bright white light as that causes temporary blindness.
Adapt eyes to darkness and avoid bright lights.
Night vision can deteriorate at cabin altitudes above 5,000ft MSL, so use supplemental oxygen if needed.
Close one eye when exposed to bright light to help avoid the blinding effect.
Do not wear sunglasses after sunset as this impairs night vision.
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 using scanning techniques.
On a clear night, distant stationary lights can be mistaken for stars or other aircraft.
Cloud layers or even the northern lights can confuse a pilot and indicate a false visual horizon.
Visual autokinesis can occur when staring 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 will not occur if the visual field is expanded through scanning techniques.
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.
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.
Flying over terrain with only a few lights makes the runway recede or appear farther away.
Bright runway lights or bold colors advance the runway, making it appear closer.
Important Pilot Equipment to have for safe night flight operations include:
Current aeronautical charts
All pertinent and accurate checklists for the aircraft
At least one reliable flashlight is recommended as standard equipment on all night flights.
A reliable incandescent or light-emitting diode (LED) flashlight able to produce white/ red light and blue for chart reading is preferable.
The flash light should be large enough to be easily located in the event it is needed.
The white light is used for preflighting the aircraft.
The red light is used for in-flight viewing of aeronautical charts since it is “non-glaring” and won’t ruin night vision.
When to turn them on:
Position Lights = On the surface and in flight from sunset to sunrise.
Beacon Light = Prior to engine start anytime day or night.
Anti-Collision Lights = All times day and night.
Unless the PIC deems they could be a safety hazard to other aircraft.
Landing Lights = Turn on for takeoff, landing and taxi operations.
Also, pilots are encouraged to turn on their landing lights below 10,000ft MSL and when within 10 miles of any airport.
Airport Beacon Lights
Civilian Land Airport = 1x White and 1x Green.
Water Airport = 1x White and 1x Yellow.
Heliport = 1x White, 1x Yellow, 1x Green.
Military Airport = 2x White and 1x Green.
Night Preflight Considerations
Night flying demands more attention to the details of preflight preparation and planning.
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
Night Cross Country Preflight Considerations
On night cross-country flights, select and use appropriate aeronautical charts to include the appropriate adjacent charts.
Course lines should be drawn in black to be more distinguishable in low-light conditions. Note prominently lighted checkpoints along the prepared course.
Rotating beacons at airports, lighted obstructions, lights of cities or towns, and lights from major highway traffic all provide excellent visual checkpoints.
If a global positioning system (GPS) is being used for navigation, ensure that it is working properly before the flight.
All necessary waypoints should be loaded properly before the flight and the database should be checked for accuracy prior to taking off and then checked again once in flight.
The use of radio navigation aids and communication facilities add significantly to the safety and efficiency of night flying.
Engine Starting, Taxiing, and Runup
Once seated in the airplane and prior to starting the engine, arrange all items and materials to be used during the flight so they will be readily available and convenient to use.
Take extra caution at night to assure the propeller area is clear.
Turning the rotating beacon ON, or flashing the airplane position lights serves to alert persons nearby to remain clear of the propeller.
To avoid excessive drain of electrical current from the battery, it is recommended that unnecessary electrical equipment be turned OFF until after the engine has been started.
After starting the engine and when ready to taxi, turn the taxi or landing light ON.
Be aware that continuous use of the landing light with revolutions per minute (rpm) power settings normally used for taxiing may place an excessive drain on the airplane’s electrical system.
Taxi slowly, particularly in congested areas. If taxi lines are painted on the ramp or taxiway, follow the lines to ensure a proper path along the route.
An instrument check should be done while taxiing to check for proper and correct operation prior to takeoff.
Use current airport diagrams and pay close attention to airport signs and markings.
Use the checklist for the before takeoff and run-up checks and procedures.
During the day, forward movement of the airplane can be detected easily.
At night, the airplane could creep forward without being noticed unless the pilot is alert.
Hold or lock the brakes during the run-up and be alert for any forward movement.
Takeoff and Climb
Flight instruments should be used to a greater degree in controlling the airplane.
This is particularly true on night takeoffs and climbs.
Adjust the flight deck lights to a minimum brightness that allow reading the instruments and switches but not hinder outside vision.
This also eliminates light reflections on the windshield and windows.
After ensuring that the final approach and runway are clear of other air traffic, or when cleared for takeoff by the air traffic controller, turn the landing and taxi lights ON and line the airplane up with the centerline of the runway.
If the runway does not have centerline lighting, use the painted centerline and the runway edge lights.
After the airplane is aligned, note the heading indicator and set to correspond to the known runway direction.
Orientation in Flight
At night, it is difficult to see clouds and restrictions to visibility, particularly on dark nights or under overcast.
When flying under VFR, pilots must exercise caution to avoid flying into clouds.
Usually, the first indication of flying into restricted visibility conditions is the gradual disappearance of lights on the ground.
If the lights begin to take on an appearance of being surrounded by a halo or glow, use caution in attempting further flight in that same direction.
Such a halo or glow around lights on the ground is indicative of ground fog.
During poor visibility conditions over water, the horizon becomes obscure and may result in a loss of orientation.
Even on clear nights, the stars may be reflected on the water surface, which could appear as a continuous array of lights, thus making the horizon difficult to identify.
Approach and Landing
Approaching the Airport
When approaching the airport to enter the traffic pattern and land, it is important that the runway lights and other airport lighting be identified as early as possible.
If the airport layout is unfamiliar, sighting of the runway may be difficult until very close-in due to the maze of lights observed in the area.
Fly toward the rotating beacon until the lights outlining the runway are distinguishable.
To fly a traffic pattern of proper size and direction, the runway threshold and runway-edge lights must be positively identified.
Once the airport lights are seen, these lights should be kept in sight throughout the approach.
Entering the Traffic Pattern
When entering the traffic pattern, always give yourself plenty of time to complete the before landing checklist. If the heading indicator contains a heading bug, setting it to the runway heading is an excellent reference for the pattern legs.
Maintain the recommended airspeeds and execute the approach and landing in the same manner as during the day.
A low, shallow approach is definitely inappropriate during a night operation.
The altimeter and VSI should be constantly cross-checked against the airplane’s position along the base leg and final approach.
A visual approach slope indicator (VASI) is an indispensable aid in establishing and maintaining a proper glide path.
After turning onto the final approach and aligning the airplane midway between the two rows of runway-edge lights, note and correct for any wind drift.
Throughout the final approach, use pitch and power to maintain a stabilized approach. Flaps are used the same as in a normal approach.
Usually, halfway through the final approach, the landing light is turned on. Earlier use of the landing light may be necessary because of “Operation Lights ON” or for local traffic considerations.
The landing light is sometimes ineffective since the light beam will usually not reach the ground from higher altitudes.
The light may even be reflected back into the pilot’s eyes by any existing haze, smoke, or fog.
The roundout and touchdown is made in the same manner as in day landings.
At night, the judgment of height, speed, and sink rate is impaired by the scarcity of observable objects in the landing area.
An inexperienced pilot may have a tendency to round out too high until attaining familiarity with the proper height for the correct round out.
To aid in determining the proper round out point, continue a constant approach descent until the landing lights reflect on the runway and tire marks on the runway can be seen clearly.
At this point, the round out is started smoothly and the throttle gradually reduced to idle as the airplane is touching down.
If the engine fails at night, there are several important procedures and considerations to keep in mind.
Maintain positive control of the airplane at the best glide airspeed.
Try to determine the cause of the engine malfunction (time permitting).
Announce the emergency on the proper radio frequency.
Turn toward an unlighted area to perform the forced landing.
Consider a landing close to a public area.
Maintain wind orientation to avoid landing downwind.
Complete the forced landing checklist.
Turn on the landing light if available.
Evacuate the aircraft immediately after landing.
FAA Sources Used for this Lesson
Airplane Flying Handbook (AFH) Chapter 10
Aeronautical Information Manual 4-3-23