Runway approach lighting system and method

An aircraft landing guidance system for visually guiding an aircraft in its landing approach to a runway having an approach area equipped with a plurality of lights operable in accordance with a plurality of intensity states including at least an off state, a low state, a medium state, and a high state, said plurality of lights being communicated to a transformer at a secondary side thereof, said transformer having a primary side with a plurality of taps including at least low, medium, and high taps that correspond respectively to said low, medium, and high states of said plurality of lights, said system comprising:

• at least one input source for requesting said plurality of lights to operate in accordance with said plurality of intensity states, said at least one input source receives a plurality of lighting intensity requests including an off request, a low request, a medium request, and a high request that correspond respectively to said low, medium, and high states of said plurality of lights, said at least one input source being capable of receiving a request for an increase in lighting intensity from one of said states to another;
• a plurality of power input lines communicated to said plurality of taps, said plurality of power input lines including a low line, a medium line, and a high line corresponding respectively to said low, medium, and high taps;
• a plurality of switches for switching between said plurality of taps of said transformer, said plurality of switches including a low tap switch in said low line, a medium tap switch in said medium line, and a high tap switch in said high line;
• and
• a control module in communication with said at least one input source and said plurality of switches, said control module having control logic for controlling operation of said plurality of switches in a predetermined sequential manner based on input received from said input source, said control logic activates at least one of said plurality of switches in response to said request for an increase in lighting intensity from said input source, said control logic first activates said low tap switch for a first predetermined time interval before activating said medium tap switch for at least a second predetermined time interval.