Precision approach path indicator: Difference between revisions

Revision as of 02:13, 18 September 2024

Revision as of 20:49, 5 November 2024

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[[Image:PAPI M39.jpg|thumb|Individual precision approach path indicator]]

PAPIs are calibrated relative to the Minimum Eye Height over Threshold (MEHT).<ref name="ICAO">{{cite book |title=ICAO Doc 9157, Aerodrome Design Manual. Fifth edition, 2021. Part 4, Visual Aids. Chapter 8 |publisher=ICAO |url=http://icscc.org.cn/upload/file/20220712/20220712090914_13813.pdf |access-date=1 March 2023 |archive-date=1 March 2023 |archive-url=https://web.archive.org/web/20230301152804/http://icscc.org.cn/upload/file/20220712/20220712090914_13813.pdf |url-status=dead }}</ref> For certain aircraft with a low pilot eye height, the pilot will see a "slightly low" indication even though they are on the ILS glideslope.<ref>https://publicapps.caa.co.uk/docs/33/CAP637%20Visual%20Aids%20Handbook.pdf {{bare URL PDF|date=May 2023}}{{Dead link|date={{subst:November}} {{subst:2024}}}}</ref> Pilot eye height is usually above the ILS receiver antenna.<ref>{{Cite web |date=2019-04-19 |title=Subject: Airbus Aircraft Data for Visual Aids Calibration |url=https://www.airbus.com/sites/g/files/jlcbta136/files/2021-11/Airbus-Aircraft-Data-for-Visual-Aids-Calibration-v5.0.pdf {{bare|url-status=live URL|archive-url=https://web.archive.org/web/20240120122413/https://www.airbus.com/sites/g/files/jlcbta136/files/2021-11/Airbus-Aircraft-Data-for-Visual-Aids-Calibration-v5.0.pdf PDF|archive-date=May2024-01-20 2023|access-date=2024-11-05 |website=Airbus |series=Issue 1.0 |id=REF:ME1911191}}</ref> [[Concorde]] had a particularly high eye height because the main undercarriage was so far behind the cockpit, so the pilots needed to land with a "slightly high" indication.<ref name="Bannister">{{cite book |last1=Bannister |first1=Mike |title=Concorde: The thrilling account of history's most extraordinary airliner |date=29 September 2022 |publisher=Random House |isbn=978-0-241-55702-0 |url=https://books.google.com/books?id=QSthEAAAQBAJ |access-date=1 March 2023 |language=en}}</ref>

The light characteristics of all light units are identical. In good visibility conditions the guidance information can be used at ranges up to {{convert|5|mi|km}} by day and night. At night the light bars can be seen at ranges of at least {{convert|20|mi|km}}.