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Google Earth @ 51°08'52.24" N 0°11'35.71" W

The markings are at 100 m intervals, to one side only of the centerline. They're also lighted as seen below.

They are missing from the ICAO aerodrome chart, and are not mentioned in CAP 637 (Visual Aids Handbook).

I measured from each threshold, but the distances to the first in each set don't match. They also don't seem to be new (judging by older satellite imagery).

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1 Answer 1


They are "Rapid Exit Taxiway Indicator Lights" as described in section 9.6 of CAP 637.

9.6 Rapid Exit Taxiway Indicator Lights

9.6.1 Rapid exit taxiway indicator lights (RETILs) provide pilots with distance to go information to the nearest rapid exit taxiway on the runway, to enhance situational awareness in low visibility conditions and enable pilots to apply braking action for more efficient roll-out and runway exit speeds.

9.6.2 RETILs consist of six yellow lights adjacent to the runway centreline and configured in a three/two/one pattern spaced 100 m apart; the single light is 100 m from the start of the turn for the rapid exit taxiway, see Figure 1.6.

  • 2
    $\begingroup$ Right! I was looking under what seemed like the logical place: chapter 2, where the runway markings are. $\endgroup$
    – user14897
    Commented May 28, 2019 at 0:47
  • $\begingroup$ They held an ICAO meeting about the missing markings (actual paint, not lights) from ICAO Annex 14, and in the proposal, the lines come with arrow heads. $\endgroup$
    – user14897
    Commented May 28, 2019 at 10:21
  • $\begingroup$ If you zoom into the map, you can see the yellow center-line for the taxiway starts right after the last mark (single slash). $\endgroup$
    – JPhi1618
    Commented May 29, 2019 at 3:09
  • 1
    $\begingroup$ The same principle as the countdown chevrons on the motorway. $\endgroup$
    – mckenzm
    Commented May 29, 2019 at 4:48

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