RWY 24 at Paris-Orly is a runway sustaining precision approaches. There is an aiming point and five touchdown zone markings.

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Orly RWY 24, source: Google Maps

Aiming the visual aiming point, or following the ILS/PAPI glideslope should bring the aircraft on the runway before the aiming point.

Why five touchdown zone markings, in particular the three after the aiming point?

Related, but not duplicates:

From the answer: "Touchdown zone marking" doesn't refer to a marking that would indicate a touchdown zone, which would imply multiple touchdown zones. Instead it refers to all markings in the single touchdown zone, including the aiming point markings.

  • 1
    $\begingroup$ I find these EASA or ICAO markings intriguing. The location differs from the FAA markings that I am used to. I am used to seeing the aiming point bars located at 300 m. Here they are at 400 m. $\endgroup$
    – J W
    Sep 3, 2016 at 16:46

1 Answer 1


ICAO Annex 14 specifies the need for 6 pairs of touchdown zone markings for runways with a landing distance available of 2400 metres or more.

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As noted in Annex 14, the number of markings relates to the landing distance available.

Presumably, the rule is there to make it easy for a pilot approaching the runway to make sure the runway is long enough if, for some reason, they are uncertain of the runway length. Similar logic could probably be applied to the rule regarding threshold markings ("piano keys"): What does the number of white bars in runway's threshold mean?

  • $\begingroup$ For instance, if an airport has two (or more) parallel runways of considerably different lengths, and a pilot is shooting a C2 ILS approach through the fog, they'd be able to tell by the number of bars whether they were following the ILS for the correct runway, or whether they'd, instead, inadvertently locked onto the one next to it. $\endgroup$
    – Vikki
    Jan 15, 2019 at 4:08

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