airport lighting

Various lighting aids that may be installed at an airport. Various types of airport lighting include approach light systems, runway lights or runway edge lights, touchdown zone lighting, runway centerline lighting, threshold lighting, runway identifier lights, vertical approach slope indicator lights, runway identifier lights, and boundary lights. An approach light system provides visual guidance to landing aircraft by radiating light beams in a directional pattern, enabling the pilot to align the aircraft with the extended centerline of the runway on his or her final approach for landing. The various categories of approach lights are ALSF-1 (approach lighting system with sequenced flasher lights in the Cat 1 configuration), ALSF-2 (approach lighting system with sequenced flasher lights in the Cat 2 configuration), SSALF (simplified short approach lights with sequenced flasher), MASLF (medium intensity short approach lights with sequenced flasher), and MALSR (medium intensity approach lights with runway lighting system). Runway edge lights, or runway lights, as they are called, indicate the lateral limits of the runway. Touchdown zone lighting indicates the area of touchdown, whereas boundary lights define the perimeter of an airport or a landing area. The functions of other lighting systems are self-explanatory.