Night Operations

Objective:       Obtain a familiarity with the factors relating to night flight and operations.

Attention:       Have the student focus on one word in a book.  Without moving the eyes, see how far they can read down the line without moving their eye.  Example of Fovea’s small focus.

Why do animals’ eyes glow when a light is shined on them?  The tapetum lucidum [tuh-pee-tuhm–lu ci dum] is a layer of tissue in the eye of many vertebrate animals that lies immediately behind or sometimes within the retina.  It reflects visible light back through the retina, increasing the light available to the photoreceptors.

How do humans develop night vision?  There is a chemical called rhodopsin, also known as visual purple.  This chemical allows the rods to become more light sensitive.  When exposed to light, it breaks down and bleaches.

Motivation:    When you understand all the different factors and risks of night flying, it brings a new exciting dimension to aviation for you.

Overview:       Factors relating to night vision, optical illusions, use of lighting, airport lighting, and night operations.

Development:

  • Factors relating to night vision
  • Lighting
  • Diet
  • General physical Health
    • Deficiencies in vitamin A affect eye’s ability to produce visual purple
      • Eye physiology [see Private Pilot textbook 10-3]
    • Define all areas of the eye: photosensitive cells called rod & cones
    • Rods
      • 10,000 times more sensitive to light than cones
      • Much of your peripheral vision
    • Cones
      • Colors
      • Things that affect night vision
      • Carbon monoxide poisoning
      • Smoking
      • Alcohol
      • Certain drugs
      • Lack of oxygen
        • Disorientation and night optical illusions
        • Empty-Field Myopia: “looking without seeing” when there seems nothing specific to focus on (in clouds or haze).
        • False horizon
        • Autokinesis: happens when you stare at a single point of light against a dark background for more than a few seconds, and it appears to move on its own.
        • Night landing: featureless terrain, dark runway environment, wide runways, mistaken approach lights, etc.
        • False Horizon: when the natural horizon is obscured or not readily apparent.
          • Runway width illusion
          • Runway and terrain slopes illusion
          • Featureless Terrain Illusion
            • Disorientation
              • Proper adjustment of interior lights
              • Bright enough to read and interpret
              • Not too bright to wash out dark sensitivity outside the aircraft
                • Importance of having a flashlight with a red lens
                • The rods on the retina are least affected by the wavelength of red light
                • Preserves night vision
                • Recommended to use only to enhance the adaptation process (~ 30 minutes)
                  • Night preflight inspection
                  • Be extra thorough as night flight has more risk
                  • Use a red flashlight to preserve night vision
                    • Unless lack of light makes you unsure, then brighter light
                      • Engine starting procedures, including use of position and anti-collision lights prior to start
                      • Turn on position lights prior to start
                      • As anti-collision lights (and landing lights) can diminish night vision (of you or other pilots), it is recommended that you not use them until ready for take-off  [see 91.209(b)]
                      • Use position lights to start
                      • Use just taxi light to taxi
                        • Taxiing and orientation on an airport
                        • Airport lighting [see Jeppesen Inst/Comm 3-16]
                        • Taxiway edge lights=blue
                        • Runway edge lights=white
                          • Pilot controlled lighting as listed in A/FM (on CTAF or UNICOM)
                            • HIRL—High Intensity Runway Lighting
                            • MIRL—Medium Intensity Runway Lighting
                            • LIRL—Low Intensity Runway Lighting
                            • Key mic within 5 seconds for 15 minutes (may vary, so see A/FM): commonly:
                              • 7 times [HIRL]
                              • 5 times [MIRL]
                              • 3 times [LIRL]
        • Instrument runways have:
        • Last 2000 feet or half of the runway [whichever is less] are amber
        • Threshold lights=green line
          • Red line at departure edge
          • Touchdown zone lights=white
          • Runway centerline lights=white
          • Taxiway centerline=green
          • Airport beacon may save your bacon
            • White and green: Lighted land airport
            • White and yellow: Lighted water airport
            • White/White and Green: Military airports—not for civilians unless dire emergency
            • PAPI—Precision Approach Path Indicator (side by side glideslope indication)
            • VASI—Visual Approach Slope Indicator (Two or three sets of two, three colors)
            • REIL—Runway End Identifier Lights—two strobes by threshold
              • Takeoff and climb-out
              • Remain over the runway
              • Consistently look for traffic and obstacles
              • Reference instruments often
                • In-flight orientation
                • Pay attention to outside references
                • Reference terrain on chart to current position
                  • Importance of verifying the airplane’s attitude by reference to flight instruments
                  • Reference instruments often
                  • Maintain proper airspeed with proper power and attitude
                    • Night emergencies procedures
                    • Fly the airplane first
                    • Troubleshoot, considering night conditions
                      • Traffic patterns
                      • Same pattern as daytime
                      • Control towers may be part time that revert to CTAF at night
                        • Approaches and landings with an without landing lights
                        • Use the PAPI/VASI and check with altimeter throughout approach
                        • When landing, use peripheral vision and look to the end of the runway
                          • Go-arounds
                          • Same as daytime

Conclusion and Evaluation:

Understand all the factors of night flying and be aware of extra possible risks.  Be able to explain the extra risks with night flying as well as factors to consider in decision making and preparing for night flying.