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In essence, if you compare EGLL and KJFK (but it works for other airports too) you would see that US airports generally adhere to the rule of 1000 ft in distance between threshold and aiming point base. In Europe there usually is an additional (2nd) pair of TDZ zone markings which brings an additional 150 m to a total of 450 m between threshold and aiming point.

What is the source of this diversification and does it change how a pilot would handle final approach in two different settings? Lower flare/harder touchdowns in US?

For simplicity let’s assume we are comparing long (i.e., 3 km or more) runways only.

EGLL example: please notice that even at EGLL there is 420 m at 3 directions but 27R is 470 m.

420 m at 3 directions at EGLL but 27R is 470 m

KJFK example:

KJFK example

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  • $\begingroup$ Are you able to provide a photographic comparison (from Google Maps perhaps)? $\endgroup$
    – BDLPPL
    Commented Oct 2, 2018 at 10:41
  • $\begingroup$ I have attached example from EGLL where same runway has different aiming point distances from TDZ. $\endgroup$
    – user2530062
    Commented Oct 2, 2018 at 20:50

1 Answer 1

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Good observation. It's often misquoted that the 1,000 feet is the [international] standard. The standards and recommendations for runway markings can be found in ICAO Annex 14. In particular section 5.2.6 for the touchdown zone marking (diagram shown below).

When a country decides it wants to deviate, it lists the differences in its AIP. In this case indeed the US AIP lists a difference from 5.2.6.4:

The U.S. standard places the aiming point marking 306 meters from the threshold where it replaces one of the pair of three stripe threshold markings. The 306 meters location is used regardless of runway length.

(Note: 306 m is ~1,000 feet.)

The UK AIP does not list a difference in distance, but the reason why it's >400 m is in a note (missing from the 2016 edition of Annex 14) in the 2017 EASA guidance material, the 400 m is the standard, except:

Where a PAPI system is provided for the runway, the beginning of the marking should be coincident with the visual approach slope origin.

The AP marker has always been (using Google Earth historic view) where the PAPI lights are at EGLL. Example for EGLL 27R:

enter image description here

When VASI is used instead of PAPI, like the 3-row VASI at OERK, it's 400 m on the mark:

enter image description here

I initially thought maybe it's because EGLL went through various lengths in its long history, but a new runway such as 05R at HECA that was built from scratch, is actually like EGLL 27R. There's more to PAPI than meets the eye.

So there is diversification indeed. As for 'landing short in the US', we are looking at ~100 m difference (306 vs. 400) for the aiming point, but don't forget the extra touchdown zone marking closer to the threshold in the ICAO standard.

enter image description here
Note: the figures apply to runways that are >2,400 m. Shorter runways have the aiming point brought closer to the threshold.

Trivia: Also still in the UK AIP is the unique aiming point, even though they are clearly no longer used at EGLL and EGCC for example (check historic view in Google Earth or current charts).

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  • $\begingroup$ I have added an image with exact measurements for EGLL where same runway can have differences on both directions (they both fall above 400 m). So I understand that the general rule and answer to my question would be that countries are free to move away from ICAO Annex 14 and they do it quite often (let's left aside reasons for that). The 1000 ft standard is misquoted indeed! $\endgroup$
    – user2530062
    Commented Oct 2, 2018 at 20:49
  • $\begingroup$ @user2530062 - Apparently I measured from the wrong part of the piano keys, see update, and I'll see if I can find more info. Quite interesting. $\endgroup$
    – user14897
    Commented Oct 2, 2018 at 21:15
  • $\begingroup$ @user2530062 - done, phew, see update. $\endgroup$
    – user14897
    Commented Oct 3, 2018 at 1:09
  • $\begingroup$ I suppose this is the correct answer. I think they have misinterpreted the rule though - I think they should have moved PAPI lights rather than markings, but obviously repaint is cheaper and maybe its chicken and egg problem. $\endgroup$
    – user2530062
    Commented Oct 3, 2018 at 7:02
  • $\begingroup$ @user2530062 - I had a thought about the reason, but found evidence against it, see update ;) $\endgroup$
    – user14897
    Commented Oct 3, 2018 at 16:40

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