How are threshold and wing bar lights spaced?
A green row across the runway end, with a wing bar either side reaching at least 10 m outward.
Threshold lights are a green row across the runway end, at right angles to the axis and not more than 3 m outside the runway end (ICAO Annex 14). On CAT II and III precision approach runways the lights are not more than 3 m apart, and on CAT I the row has at least as many lights as 3 m spacing would give; on other runways there are at least six.
Wing bars are added either side to make the threshold stand out: at least five lights, extending at least 10 m outward at right angles to the line of the edge lights, with the innermost light in that line.
Barrette pairs either side, 30 m or 60 m apart. See Entry 35.
Green row across the end, with wing bars reaching outward.
Frequently Asked Questions
Q1What are runway threshold lights?
Threshold lights are a row of green lights, showing toward the approaching aircraft, laid across the runway at the threshold. They mark the start of the usable runway for the pilot.
Q2Where is the threshold light row placed?
On a line at right angles to the runway axis, as near to the runway end as possible and not more than 3 m outside it, according to ICAO Annex 14 Volume I.
Q3How far apart are threshold lights?
On CAT II and III precision approach runways the row is spaced at not more than 3 m; on CAT I it has at least as many lights as 3 m spacing would give. Either way the number of lights depends on the runway width. On a non-instrument or non-precision runway there are at least six lights, evenly spaced or in two groups about the centreline. Confirm the figures in the current edition.
Q4What are wing bars?
Wing bars are short rows of green lights added either side of the threshold to make it easier to see. Each has at least five lights extending at least 10 m outward from the line of the runway edge lights, at right angles to it.
Q5Where does a wing bar start?
The innermost light of each wing bar sits in the line of the runway edge lights, and the bar runs outward from there, away from the runway.
Q6Where are threshold and wing bar lights defined?
In ICAO Annex 14 Volume I (Chapter 5, runway threshold and wing bar lights) and the Aerodrome Design Manual Part 4, and for FAA-regulated airports in FAA AC 150/5340-30 and the project specification. Always confirm against the current edition.
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