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F4 and G4 Tower Types

The F4 and G4 tower types are over 1050′ tall but not more than 1400′ excluding any appurtenances and are lit by 8 L-864 red medium intensity beacons and 12 L-856 white high intensity beacons.


FAA AC 70/7460-1M

  • Dual L-864/L-864 beacons include red, infrared and white LEDs.
  • L-864 red/infrared beacons must flash in sync at 30 fpm.
  • Infrared LED strings must be monitored, and an IR outage is a NOTAM-worthy event.


FAA AC 70/7460-1L

  • L-864 beacons must flash in sync at 30 flashes per minute
  • No L-810 marker lights are required


FAA AC 70/7460-1K, FAA AC 70/7460-1J and FAA AC 70/7460-1H

  • L-864 beacons set to 20-40 flashes per minute
  • 12 L-810 steady-burning marker lights


F4 Towers

  • F towers have appurtenances greater than 40′ and 1 L-864/L-865 dual medium intesity beacon is required on top


G4 Towers

  • G towers have no appurtenances greater than 40′ so no dual L-864/L-865 beacon is required