How is a taxiway fixture selected?
Four decisions, taken in order, that narrow the choice to the right type of taxiway light.
Choosing a taxiway fixture is a short chain of decisions. Position decides inset or elevated: centreline and stop-bar lights are normally inset in the pavement (a stop bar may also have elevated lights), while edge lights are normally elevated. Beam follows the job: edge lights are seen from all sides and are omnidirectional, while centreline lights are aimed along the route.
Colour comes from the function, blue for the edge and green for the centreline (alternating green and yellow on exit-taxiway sections near the runway), with red for stop bars. The light source follows the circuit and maintenance plan. The final fixture is confirmed against the colour and photometric requirement, the series circuit and transformer, and the mounting or load rating.
Frequently Asked Questions
Q1How is a taxiway light fixture selected?
By working through a few decisions in order: where the light sits on the taxiway, whether it must be seen from all sides or along the route, the colour its function requires, and the light source and circuit it will run on. The result is then checked against the data sheet.
Q2Why are taxiway edge lights omnidirectional but centreline lights directional?
Edge lights outline the taxiway and are seen by pilots from many angles, so they shine in all directions. Centreline lights guide an aircraft along a route, so their beam is aimed along that route.
Q3What colours are used on taxiway lights?
Blue for edge lights and green for centreline lights, which alternate green and yellow on exit-taxiway sections near the runway. Stop bars are red. The colour comes from the function of the light, so it is part of the fixture specification and not a free choice.
Q4When is an inset fixture used instead of an elevated one?
Centreline and stop-bar lights normally sit in the pavement and use inset fixtures; a stop bar may also have elevated lights. Edge lights are normally elevated, but an inset fixture is used where the layout does not allow an elevated one, for example where aircraft or vehicles must cross the edge.
Q5What should be checked before the choice is final?
That the fixture meets the required colour and photometric performance, suits the series circuit current and transformer, and has the correct frangibility or load rating for its position. The manufacturer's data sheet and the applicable standard decide.
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