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If you see KRDM RNAV Y RWY 29 - airport elevation is 3080. But in RNAV Z RWY 29 - airport elevation is 3082. How it can be different for approaches to the same airport and runway?

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To add to the correct answer by RTO, a survey was completed on Jan 26, 2019. The airport elevation is 3081.5 (which rounds to 3082 on the chart). See the snippet of eNASR below.

The procedure documentation for the RNAV (GPS) Y RWY 29 was amended for the 28FEB19 effective date (to add the VGSI and RNAV glidepath not coincident note). The results of the survey were likely not yet available for publication when the chart was updated.

The procedure documentation for the RNAV (GPS) Z RWY 29 is similar, but it was updated via transmittal letter (TL) 22-13. It specifically updates the ELEV, among other things. (Link below)

Snippet from eNASR

Snippet from IFPG https://www.faa.gov/aero_docs/acifp/NDBR/96980669FE9542F7B95214A1951A1012-RDM-NDBR/P-NOTAM_OR_RDM_RGZ29_AMDT%201B.pdf

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  • $\begingroup$ Thanks for the info! $\endgroup$
    – user22445
    Commented Oct 18, 2023 at 20:08
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The only explanation I can see is that the "Y" approach is dated 28 Feb, 2019 and the "Z" approach is dated 16 Jun 2022.

Perhaps a new survey of the airport elevation was done after the "Y" approach was published.

Airport Elevation is defined as: (FAA Aeronautical Chart User's Guide, page 120)

[...] "The airport elevation is the highest point of an airport’s usable runways measured in feet from mean sea level."


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    $\begingroup$ I think this is correct. I can point to a few examples where the same runway is shown with a different elevation shown on two different approach charts. Jeppesen just reproduces what they're given by the government that publishes the information, so when the government doesn't update every procedure to reflect a particular change, you get situations like this. Thankfully, a difference of a foot or two in TDZE is really in the "measure with a micrometer, mark with chalk, cut with the chainsaw" category of useless precision. $\endgroup$
    – Ralph J
    Commented Oct 17, 2023 at 18:59

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