Introduction
Flying at night presents new challenges, such as reduced visibility and disorientation, requiring additional skills and heightened awareness. Pilots must be aware of the risks and operate within their abilities and limitations.
The additional risks of flying in darkness must be identified and assessed. Pilots must consider physical limitations, equipment requirements, and emergency planning. Although pilots cannot eliminate all night flying risks, careful preflight preparation and knowledge of these factors can make them safer.
Objectives
After this lesson, the learner will be able to describe:
- Physiological factors associated with night operations, including optical illusions and dark adaptation.
- Preflight inspection procedures that are unique to night operations.
- Airport operations that are applicable to night operations.
- Emergency procedures at night.
Teaching Strategy
This lesson consists of a ground discussion (theory) and assessments of the training airplane at night (practical).
Autokinesis Demonstration
Place a laser light on a fixed object such as a table and aim it at a wall. With the room dark, have the learner trace the light’s motion on a piece of paper for a couple of minutes. Then reveal that the laser light remained in a fixed position.
Light Trails Demonstration
In a dark room, shine the laser light against a wall and move it rapidly in a small circular pattern. Note the trails of light that remain where the penlight has been. The light trails are a result of the slowness of the rod system.
Night Color Blindness Demonstration
In a dimly lit room with the eyes adapted, notice the lack of color in the dimmest areas. Buts objects that are sufficiently bright have color. This is the difference between the rods (night vision) and cones (day vision).
Night Blind Spot Demonstration
In a dimly lit room with the eyes adapted, find a dim (dark) object on a darker background. Note that the object is not visible when viewed directly but is more visible when viewed peripherally. This is due to the absence of rods in the fovea.
Lesson Presentation
- Night Operations
- Operation of Aircraft Lights
- Recommended Usage of Exterior Lighting
- Control of Airport Lighting
- Illusions in Flight
- VFR-Night Instruments and Equipment
- Night Considerations for Navigation and Flight Planning [VFR]
- Night Considerations for Preflight Inspections
- Night Considerations for Engine Starting
- Night Considerations for Taxiing
- Night Considerations for Takeoffs
- Night Considerations for Landings
- Night Considerations for Go-Arounds
- Night Considerations for Emergency Landings
Aircraft Specific Training
- Limitations in the AFM/POH specific to night operations, if applicable
- How to determine if a piece of equipment is required to be operative for night flight
- Procedures for inspecting and operating the interior and exterior lights
Risk Management
- Collision avoidance, visual scanning, obstacle and wire strike avoidance
- Improper planning to avoid terrain
- Failure to maintain situational awareness
- Environmental considerations at night
- Failure to maintain VFR
- Physiological aspects of night flying
Scenario
A friend has asked you to take him and his fiancee up for a night flight to look at the city lights. You have not flown at night for several months, so you need to make a short solo flight to build proficiency and complete the required landings for currency requirements.
Case Studies
A Cessna 400 on a night, cross-country flight experiences a loss of engine power accompanied by extreme vibrations:
- Aircraft: Cessna 400
- Location: Martinsburg, PA
- Date: August 31, 2008
- AOAP Video: https://youtu.be/EYUkExyObt8
Resources
- Airplane Flying Handbook (FAA-H-8083-3):
- Chapter 11, Night Operations
- Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25):
- Chapter 17, Aeromedical Factors
- Aeronautical Information Manual (AIM):
- 2-1-2: Visual Glideslope Indicators
- 2-1-3: Runway End Identifier Lights (REIL)
- 2-1-4: Runway Edge Light Systems
- 2-1-5: In-runway Lighting
- 2-1-7: Control of Lighting Systems
- 2-1-8: Pilot Control of Airport Lighting
- 2-1-9: Airport/Heliport Beacons
- 2-1-10: Taxiway Lights
- 4-3-23: Use of Aircraft Lights
- 8-1-5: Illusions in Flight
- 8-1-6: Vision in Flight
- AOPA Safety Quiz: Night Operations
Schedule
- Lesson Presentation (0:25)
- Preflight Demonstration at Night (0:15)
- Break (0:10)
- Review and Assessment (0:15)
Equipment
- Whiteboard, markers, and erasers
- Flashlights, to include a variety of lens colors
- Preflight inspection checklist
- An airplane for a preflight demonstration
Review and Assessment
This lesson concludes with a combined informal assessment and review of the main points.
Additionally, the instructor ensures:
- All of the learner’s questions are resolved.
- The learner is made aware of his or her performance and progress.
Completion Standards
This lesson is complete when the lesson objectives are met and the learner’s knowledge is determined to be adequate for the stage of training. Ultimately, the learner must meet or exceed the Airman Certification Standards.
Lesson Content
Night Operations
Reference: AIM 8-1-6
Adjustment to Light
Rods in the eyes take more time to adjust to changes in light than the cones. The eyes adapt to sunlight in 10 seconds, but at least 30 minutes is required for the rods to adjust to the dark fully. The adjustment of the eye to low light intensities is called dark adaptation.
Note: Since dark adaptation can be lost very quickly, pilots should close one eye before turning on a light to preserve night vision in the other eye.
Night Blind Spot
Due to the absence of rods in the fovea, a central blind spot is created at night. The blind spot exists in an area between 5° and 10° wide in the center of the visual field. Pilots can more clearly see an object at night by not looking directly at it but rather looking to one side.
Visual Scanning at Night
Visual search at night depends almost entirely on peripheral vision. The rods must be exposed to the image. To perceive a dimly lit object, the pilot should not look directly at the object but scan the area adjacent to it.
To scan effectively, pilots must look from right to left or left to right in sections that are approximately 30° wide. When moving from one viewing point to the next, pilots should overlap the previous field of view by 10°. Each section should be scanned for no longer than 2 to 3 seconds. These short pauses help detect light and its movement.
Cockpit Lighting
Cockpit lighting should be kept as low as possible so that the light does not deteriorate night vision. When it is necessary to read charts and checklists, pilots should use a dim white light and avoid shining it directly into the eyes. Red light can help preserve nighttime vision but makes red nearly invisible on aeronautical charts.
Position Lights
Airplane position lights provide a means to determine the general direction of movement of other airplanes in flight. A red light is positioned on the left wingtip, a green light on the right wingtip, and a white light on the tail.
When a red and green light of another aircraft is observed:
- If the red light is on the left and the green to the right, the airplane is flying in the same direction.
- If the red light is on the right and green to the left, the airplane could be on a collision course.
Operation of Aircraft Lights
References: 14 CFR 91.205, 14 CFR 91.209, Letts (2017) Legal Interpretation, Murphy (2011) Legal Interpretation
During the period from sunset to sunrise, no person may:
- Operate an aircraft unless it has lighted position lights,
- Move an aircraft unless the aircraft:
- Is clearly illuminated;
- Has lighted position lights; or
- Is in an area that is marked by obstruction lights.
At any time, no person may:
- Operate an aircraft that is equipped with an anticollision light system unless it has lighted anticollision lights. However, the anticollision lights need not be lighted when the PIC determines that, because of operating conditions, it would be in the interest of safety to turn the lights off.
If an airplane is equipped with anticollison lights, they must be operational. The inoperative equipment provisions of 14 CFR 91.213 do not apply. However, 14 CFR 91.205 states that operations with the aircraft (day or night) may be continued to a stop where repairs or replacements can be made.
If an aircraft is equipped with both strobe lights and a rotating beacon, both are considered part of the anticollision system, and both must be operational.
Recommended Usage of Exterior Lighting
References: 14 CFR 91.209, AIM 4-3-23, AC 91-73, SAFO 11004
- Engines Running: Beacon ON
- Sunset to Sunrise: Position lights ON
- Taxi (While Moving): Taxi light ON
- Taxi (When Stopped or Yielding): Taxi light OFF
- Crossing a Runway: All exterior lights ON
- Line Up and Wait: Landing light OFF; All other exterior lights ON
- Takeoff and Landing: All exterior lights ON
- Climb and Descent: All exterior lights ON
Note: Pilots should consider the effects of illuminating strobe and forward-facing lights on the vision of other pilots or ground personnel. These lights should not be illuminated during taxi if they adversely affect safety.
Control of Airport Lighting
References: AIM 2-1-7, AIM 2-1-8, Chart Supplements
ATC controls airport lighting at towered airports. A pilot may request various light systems be turned on or off and also request a specified intensity, if available.
At nontowered airports, the lights may be on a day/night timer, or the pilot may control the lighting by radio. The lighting intensity can be changed by selecting a specified frequency and clicking the radio microphone. Lights typically remain on the selected intensity for 15 minutes.
Key Mike | Function |
7 times within 5 seconds | Highest intensity available |
5 times within 5 seconds | Medium or lower intensity (lower REIL or REIL off) |
3 times within 5 seconds | Lowest intensity available (lower REIL or REIL off) |
Illusions in Flight
Reference: AIM 8-1-5
Illusions in flight can related to the vestibular or visual systems. These illusions can lead to spatial disorientation, approach and landing mishaps, and errors in visual scanning and collision avoidance.
Visual Illusions Leading to Spatial Disorientation
False Horizon Illusion: Occurs when the pilot confuses cloud formations with the horizon or the ground. A sloping cloud deck may be perceived as horizontal, although it may not be level to the ground; thus, the pilot may fly the airplane in a banked attitude. The illusion may result in the pilot placing the airplane parallel to the clouds.
Relative-Motion Illusion: The falsely perceived self-motion in relation to the motion of another object.
Example: An aircraft is stopped in the run-up area and another airplane pulls alongside. The pilot stopped in the run-up area perceives the second airplane’s forward motion as his or her movement.
Flicker Vertigo: While technically not an illusion, viewing a flickering light can be distracting. Flicker vertigo may be created by airplane propellers interrupting direct sunlight at a rate of 4–20 cycles per second. Flashing strobe lights, especially in the clouds, can also produce this effect.
Confusion with Ground Lights:
- Ground lights can be mistaken for stars. This illusion prompts the pilot to place the airplane in an unusual attitude to keep the lights above them.
- When no stars are visible because of overcast conditions, unlighted areas of terrain can blend with the sky.
Visual Illusions Related to Visual Scanning and Collision Avoidance
Autokinesis: Occurs at night when ambient visual cues are minimal, and a small, dim light is seen against a dark background. After 6–12 seconds of visually fixating on the light, one perceives movement at up to 20° in any particular direction or in several directions in succession, although there is no actual movement.
Size-Distance Illusion: When one stares at a point of light, it may appear to approach or recede rapidly. A change in the intensity of the light can cause this illusion. When a light gets suddenly brighter, it may appear much closer.
Reversible Perspective: At night, an aircraft may appear to be moving away from an observer when it is approaching. To eliminate this illusion, use the position lights and their relative arrangements to determine the aircraft’s orientation and motion.
Visual Illusions Leading to Landing Errors
Runway Width Illusion: A narrower-than-usual runway can create the illusion that the airplane is too high. The pilot who does not recognize this illusion will fly a lower approach, risking impact with the ground short of the runway. A wider-than-usual runway has the opposite effect.
Runway and Terrain Slopes Illusion: An up-sloping runway can create the illusion that the airplane is higher than it is. The pilot who does not recognize this illusion will fly a lower approach. A down-sloping runway can have the opposite effect.
Featureless Terrain Illusion (“Black Hole Approach”): An absence of ground features can create the illusion that the airplane is at a higher altitude than it is. The pilot who does not recognize these illusions will fly a lower approach.
Atmospheric Illusions:
- Rain on the windshield can create the illusion of greater height, and atmospheric haze can create the illusion of being a greater distance from the runway. The pilot who does not recognize these illusions will fly a lower approach.
- Penetrating fog can create the illusion of pitching up. The pilot who does not recognize this illusion will abruptly steepen the descent.
Ground Lighting Illusions:
- Streetlights or other lights along a straight path can be mistaken for runway or approach lights.
- Bright runway lights may create the illusion of less distance to the runway. The pilot who does not recognize this illusion will fly a higher approach.
Best Practices for Preventing Landing Errors Due to Visual Illusions
- Anticipate visual illusions during approaches to unfamiliar airports, particularly at night or in adverse weather conditions.
- Consult airport diagrams and the Chart Supplement for information on runway slope, terrain, and lighting.
- Make frequent reference to the altimeter and vertical speed indicator.
- Use Visual Approach Slope Indicator (VASI) or Precision Approach Path Indicator (PAPI) systems for a visual reference, or an electronic glideslope, whenever they are available.
- Utilize the visual descent point (VDP) found on many nonprecision instrument approach procedure charts. [IFR]
VFR-Night Instruments and Equipment
References: 14 CFR 91.205, 14 CFR 91.209
For a night flight under VFR, the following instruments and equipment are required to be in an operable condition for civil aircraft with a Standard Airworthiness certificate. All of the instruments and equipment for a VFR-day flight are also required.
Mnemonic: FLAPS
- Fuses (one spare set of fuses, or three spare fuses for each kind required, that are accessible to the pilot in flight)
- Landing light (an electric landing light if the aircraft is operated for hire)
- Anticollision lighting system (approved aviation red or white)
- Position lights
- Source of electricity (an adequate source of electrical energy for all installed electrical and radio equipment)
Notes: In the event of failure of any light of the anticollision light system, operations with the aircraft may be continued to a stop where repairs or replacements can be made.
Night Considerations for Navigation and Flight Planning [VFR]
- Airport beacons and city lights make good checkpoints. City lights correspond to the yellow outlines on VFR charts.
- Routes should be planned to keep the aircraft close to suitable airports for use in an emergency.
- Continuously monitor position, time estimates, and fuel consumed. Use NAVAIDs to assist in monitoring en route progress.
- A narrow temperature/dew point spread may indicate the possibility of fog.
- Personal minimums should be raised as an added safety margin.
- Identify areas that are below VFR weather minimums.
- Crossing large bodies of water at night is hazardous because the horizon may blend with the water.
Night Considerations for Preflight Inspections
- Ensure that the aircraft is equipped for night operations per 14 CFR 91.205.
- Carry at least two flashlights; a bright one for the preflight and a smaller one to use while flying.
- Parking ramps should be checked with a flashlight before entering the airplane.
- Inspect all interior and exterior lighting for proper operation. Tap the light fixtures to check for loose connections.
Night Considerations for Engine Starting
Reference: 14 CFR 91.209
- Use extra caution to ensure the propeller area is clear.
- The position (navigation) lights should be turned ON after engine start.
- The anticollision lights are not required to be ON if the PIC determines that it would be in the interest of safety to leave them OFF.
Night Considerations for Taxiing
- Taxi slowly, particularly in congested areas.
- Use extra caution when entering or crossing a runway.
- Avoid using the strobe lights and bright, forward-facing lights around other aircraft.
- When stopped, use extra vigilance to ensure the airplane does not creep forward.
- Adjust the interior lights to a minimum brightness that allows reading the instruments and switches. Dimming the lights reduces reflections on the windows.
Night Considerations for Takeoffs
- Use extra vigilance when entering the runway. Approaching aircraft may not be equipped with or be using landing lights.
- Use caution for wildlife. Deer and other mammals are active at night.
- During the takeoff roll and immediately after liftoff, keep the runway lights parallel to the direction of motion.
- Cross-check the flight instruments after liftoff to help maintain the climb attitude.
- Do not turn until reaching a safe maneuvering altitude.
Night Considerations for Landings
- Distances and height can be deceptive. Use slope indicators to help maintain the approach angle.
- Check NOTAMS for unlit obstacles and runway closures.
- Beginning pilots tend to round out too high. The flare should begin when the landing lights reflect on the runway and tire marks can be seen clearly.
- When landing without a landing light, the flare should begin when the far-end runway edge lights appear to rise above the nose.
- Use caution for wildlife. Deer and other mammals are active at night.
Night Considerations for Go-Arounds
Reference: SAFO 15004
- A loss of control is more likely at night, where spatial disorientation is most likely. Cross-check the flight instruments to help maintain the climb attitude.
- Execute a go-around immediately if visual contact is lost with the landing runway. High terrain could be obstructing the view.
Night Considerations for Emergency Landings
If the engine fails at night, incorporate the following procedures:
- If the nearby terrain’s condition is known and suitable for a forced landing, turn towards an unlighted portion of the area and plan an emergency forced landing to an unlighted portion.
- Turn the landing lights ON in time to illuminate the terrain or obstacles.
- If outside visual references are not available, maintain a level-landing attitude until the ground is contacted.