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Light Gun Signals

Introduction:

  • Light gun signals are a tool used by Air Traffic Control Towers (ATCT) when:
    • No radio is equipped on the aircraft
    • Communications cannot be established, or
    • During communication malfunctions [Figure 1]
  • Applies not only to aircraft, but to ground vehicles, equipment, and personnel not equipped with radios
  • ATC personnel use a directive traffic control signal which emits an intense narrow light beam of a selected color (either red, white, or green) when controlling traffic by light signals

Light Gun Procedures:

  • Terminal Area:

    • If radios go out in the terminal area, circle the field and wait for light gun signals
    • If no signals appear evident after a sufficient amount of time waiting, begin an approach when traffic has been determined and de-conflicted and land on the active runway (as dictated by traffic and wind) and look for light gun signals
    • If in the pattern and no light gun signals are observed, wave-off your first approach and continue in the pattern for a full stop
    • If radio malfunction occurs after departing the parking area, watching the tower for light signals or monitor tower frequency
  • Day:

    • Rock your wings to get towers attention and acknowledge towers instructions or light signals by moving the ailerons or rudder
  • Night:

    • At night, acknowledge by blinking the landing or navigation lights
    • Between sunset and sunrise, a pilot wishing to attract the attention of the control tower should turn on a landing light and taxi the aircraft into a position, clear of the active runway, so that light is visible to the tower
      • The landing light should remain on until appropriate signals are received from the tower

Notes:

  • A green light means you are cleared to land on any runway
  • Signals can be difficult to see during the day, especially if you're trying to fly and look at the tower [Video 1]
    • At night, light signals as you can imagine are easy to see, but from towers point of view, you may not
    • Complicating matters, if you have an electrical issue causing your inability to communicate, you may not have working lights either
  • Disadvantages:
    1. Pilots may not be looking at the control tower at the time a signal is directed toward their aircraft
    2. The directions transmitted by a light signal are very limited since only approval or disapproval of a pilot's anticipated actions may be transmitted
      • No supplement or explanatory information may be transmitted except by the use of the "General Warning Signal" which advises the pilot to be on alert

ATC Light Gun Signals
Professional Helicopter Pilots Association Light Gun Signal Card

Conclusion:

  • Although the traffic signal light offers the advantage that some control may be exercised over nonradio equipped aircraft, pilots should be cognizant of the disadvantages

References: