Night flying

Night Flight

Night flight definition

  • Night means the time between the end of evening civil twilight and the beginning of morning civil twilight
  • In the morning, civil twilight begins when the centre of the sun’s disc is 6° below the horizon and is ascending, and ends at sunrise, approximately 25 min later.
  • In the evening, civil twilight begins at sunset, and ends when the centre of the sun’s disc is 6° below the horizon and is descending, approximately 25 min later.
(Canadian rules).

Airplane Equipment

In addition to the aircraft equipment required for Day VFR flight :

  • Sensitive altimeter.
  • Turn and Bank indicator or turn co-ordinator.
  • A means of illuminating instruments;
  • Position and anti-collision lights.
  • Timepiece.
  • Flashlight.
  • when operated beyond visual range of an aerodrome:
    • A gyroscopic or stabilized magnetic direction indicator.
  • Controlled airspace:
    • Two way communication.
  • when carrying passengers :
    • Landing light.

Airport Lighting

  • Taxiway Lights : Blue.
  • Runway End lights: Red.
  • Runway Edge Lights: White (single row on either side of runway edge).
  • Center line lights:
    • White until 3000 ft.
    • 3000 – 1000 ft. alternating Red and White.
    • Last 1000 ft. Red.
  • Runway Threshold Lights: Green.

Aircraft Lighting

  • Position Lights:
    • Right Wing : Green.
    • Left Wing: Red.
    • Tail : White.
  • Rotating Beacon : Red
  • Strobes : Flashing White.
  • Taxi and Landing: White.

ARCAL ( Aircraft Radio Control of Aerodrome Lighting)

  • Used at non-controlled airport.
  • System which allows aircraft pilots to control the lighting of an airport or airfield’s approach lights, edge lights, and taxiways via radio.
  • To activate the lights, the pilot clicks the radio transmit switch on the ARCAL frequency a certain number of times within a specified number of seconds.
  • There are two types of ARCAL systems, type J and type K.
  • Type J:
    • Click the microphone 5 times within 5 seconds.
    • 15 minutes duration.
  • Type K:
    • Click the microphone 7 times within 5 seconds for max intensity.
    • Intensity may be adjusted by keying 7 (high), 5 (medium) or 3 (low).
    • 15 minutes duration.

VASI and PAPI

  • VASI (Visual Approach Slope Indicator).
    • Provide glideslope angle of approximately 3 degrees.
    • The 2-bar VASIS has 2 ranks of lights.
    • The 3 bar VASIS has 3 ranks of lights.
  • PAPI (Precision Approach Path Indicator).
    • Provides a more precise glideslope indication than does VASIS.
VASI (2-bar)
PAPI

Air traffic contol light signals

  • Used by ATCT’s in the control of aircraft, ground vehicles, equipment, and personnel not equipped with radio.

Night Vision

  • Eyes have RODS and CONES.
  • CONES
    • are best for Day vision and color.
    • During the day an object is seen best by looking directly at it.
  • RODS
    • are best for peripheral vision and night vision.
    • During night VFR flying, offcenter viewing will allow a pilot to see objects.

Dark Adaptation

  • Dark adaptation is the adjustment of the human eye to a dark environment.
  • The rods can take approximately 30 minutes to fully adapt to darkness.
  • Protect your night vision by using a red light in the cockpit.
  • Avoid bright white lights or flash (can completely destroy your night adaptation).
  • May be impaired by flying above 5,000 ft.

Visual Illusions

  • Black hole.
  • Bright Runway Lights.
  • Vertigo.
  • Autokinesis.
  • Distant Stationary Lights.
  • False Horizon.
  • Upslope and downslope runway.
Black hole:
  • Occurs when the landing is made from over water or non-lighted terrain where the runway lights are the only source of light.
  • During a black-hole approach the pilot can have trouble orienting himself relative to the earth. The runway may seem to be upsloping or downsloping.
  • Counter this illusion by using available approach aids such as VASIs or PAPIs.
Bright Runway Lights:
  • Bright runway lights advance the runway, making it appear closer than it actually is.
  • In this situation,the pilot who does not recognize this illusion may fly a higher than normal approach.
  • Counter this illusion by using available approach aids such as VASIs or PAPIs.
Ground Lighting Illusion:
  • Lights along a road or even trains can be mistaken for runway and approach lights.
Vertigo:
  • Can occur by intermittent lights in the cockpit.
  • Can cause dizziness, nausea and general disorientation.
Autokinesis:
  • An isolated fixed light may appear to move around.
  • Can be avoided by continuing a visual, offcentered scan.
Distant Stationary Lights:
  • Can be confused for stars or other aircraft.
  • Confirming what is visually seen outside the aircraft with the aircraft instruments can eliminate the distant stationary light illusion.
False Horizon:
  • A dark scene with ground lights and stars as well as certain geometric patterns of ground lights can create illusions of not being aligned correctly with the actual horizon.
Upslope and downslope runway illusions
Narrow or Wide Runways illusions

Night Flying Procedures

Preflight check:
  • Check lights
    • Cockpit and panel lights
    • Landing/taxi lights
    • Nav lights
    • Flashlight
    • Strobes
    • Beacon
Taxiing:
  • Taxi slower than normal.
  • Use taxiway lines to ensure guidance and clearance.
Run-up:
  • In addition to normal run-up, adjust cabin lights for night vision.
Takeoff, Climb and Departure:
  • Complete normal checklists
  • Use trim and landing lights
  • Maintain direction by reference to runway lighting, then by other lighted objects ahead.
  • At correct speed rotate to the climb attitude by looking outside, AND the instruments.
    • Ensure aircraft continues a positive rate of climb by monitoring the altitude indicator and Vertical Speed Indicator.
  • Instruments will need to be checked more frequently for airspeed, heading and attitude.
  • Check Heading Indicator and adjust for drift
  • Once beyond 10 miles from any airport or air traffic congestion, turn the landing light & taxi light off.
Cross Country:
  • Clouds can be difficult to see during the night.
    • One of the first indication of flying into bad visibility conditions is the gradual disappearance of lights on the ground.
  • Use flashlight for map reading.
  • Use lighted landmarks.
  • Use Navaids (VOR radials, NDB beairing) to check your position.
  • Be aware of all lit and unlit obstructions which may pose a hazard on your route of flight.
Approach:
  • In an unfamiliar area, the runway may be hard to identify, and in this case, look for the beacon.
  • Distances, altitudes, and airspeeds cannot be determined as well as during the day (due to lack of references) thus a reliance on instruments may be required more.
  • Correct approach path:
    • The runway lights will appear to remain equidistant.
  • Overshooting approach path:
    • The distance between the lights appears to increase.
  • Undershooting approach path:
    • The distance appears to decrease.
  • No low flat approach.
Landing:
  • As possible, landings at night should be no different than landings during the day.
  • On final, align the aircraft with the runway lights, and when possible, use the VASI for glide slope information
  • Make sure the landing light is on to assist with the landing.
  • Be careful to the tendency to make approaches with excessive speed.
  • Landing light illuminates threshold area,
  • Round out and touchdown should be made in the same manner as day, but your judgement of height, speed, and sink will be impaired.
    • Use end light to judge sink rate.

Review questions

  • At night, what is the minimum flight visibility required to operate an aircraft VFR at less than 1000 ft AGL ?
  • For night vision, it takes time for our eyes to fully adapt to the dark. In general, approximately how long will this process take?
  • What colour are threshold lights?
  • How can you tell if you are undershooting the runway during a night time approach?