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Include the approach plate inline
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CrepuscularV
CrepuscularV
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I had assumed during a WAAS approach when the GPS is in LPV mode, both lateral guidance and vertical guidance are generated from GPS/WAAS signals and the pitot-static system should have no effect on its vertical guidance. This is in contrast with LNAV/VNAV approach, where the vertical guidance comes from the barometric system, the same source as altimeter.

However, when I read RNAV (GPS) Z RWY 30 @ KHAF, I will get a different DA if I use a different altimeter setting. So, why does altimeter settings matter to the DA in an LPV approach?

enter image description here

I had assumed during a WAAS approach when the GPS is in LPV mode, both lateral guidance and vertical guidance are generated from GPS/WAAS signals and the pitot-static system should have no effect on its vertical guidance. This is in contrast with LNAV/VNAV approach, where the vertical guidance comes from the barometric system, the same source as altimeter.

However, when I read RNAV (GPS) Z RWY 30 @ KHAF, I will get a different DA if I use a different altimeter setting. So, why does altimeter settings matter to the DA in an LPV approach?

I had assumed during a WAAS approach when the GPS is in LPV mode, both lateral guidance and vertical guidance are generated from GPS/WAAS signals and the pitot-static system should have no effect on its vertical guidance. This is in contrast with LNAV/VNAV approach, where the vertical guidance comes from the barometric system, the same source as altimeter.

However, when I read RNAV (GPS) Z RWY 30 @ KHAF, I will get a different DA if I use a different altimeter setting. So, why does altimeter settings matter to the DA in an LPV approach?

enter image description here

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CrepuscularV
CrepuscularV
  • 3.4k
  • 3
  • 25
  • 56

Does altimeter setting affect the vertical guidance in a LPV approach?

I had assumed during a WAAS approach when the GPS is in LPV mode, both lateral guidance and vertical guidance are generated from GPS/WAAS signals and the pitot-static system should have no effect on its vertical guidance. This is in contrast with LNAV/VNAV approach, where the vertical guidance comes from the barometric system, the same source as altimeter.

However, when I read RNAV (GPS) Z RWY 30 @ KHAF, I will get a different DA if I use a different altimeter setting. So, why does altimeter settings matter to the DA in an LPV approach?