Abstract: A runway lighting system comprises a series runway transmission line providing current to a plurality of runway lamps. A failed lamp indicator (FLI) connects across the terminals of each lamp to determine when the lamp is malfunctioning. When the FLI determines that a lamp is malfunctioning, the FLI transmits a malfunction signal, during a specific time period defined in lamp address circuitry in each FLI, onto the existing series runway transmission line. A circuit status analyzer (CSA), which forms part of the vault computer, receives the malfunction signal, noting the time period during which the signal was received. The CSA then accesses an internal ROM look-up table to determine which FLI sent the signal.

Abstract: An improved runway lighting system comprises a first set of runway lights providing illumination in one direction along the runway, a second set of runway lights providing illumination in the opposite direction along the runway and a switching unit for switching on either the first set of lights or the second set of lights, depending on the direction of approach of incoming aircraft. A control unit provides current pulses along existing runway circuitry to operate the switching unit. Circuitry in the switching unit determines which set of lights to illuminate based upon the amplitude and duration of the current pulse. A selector switch may also be provided in the control tower to remotely operate the control unit.