Garmin Fishfinder 80 User Newsletter - page 4
Above is a portion of the RNAV 31 Z approach at KSLE which may be flown as an LPV, Lnav/Vnav, or Lnav only approach. The
LPV precision approach is depicted in the same fashion as an ILS would be in the profile view. The additional waypoint (CUKEV) is
only applicable if flying the approach as an LNAV approach, and the additional missed approach arrows are depicted for each type of
approach. Notably this approach has an odd situation where the Lnav/Vnav minimums are higher than the Lnav minimums as the
result of TERPS obstacle clearance criteria. In this case a tower penetrated the vertical path causing the Lnav/Vnav minimums to be
raised. You should also remember that if vertical guidance for an Lnav/Vnav approach can be supported, so can the LPV. In this
case, there would never be a reason to fly the Lnav/Vnav approach, just the LPV. If WAAS could not support the LPV approach, an
Lnav only approach would be possible.
Above is a portion of the GPS 17 approach at KCVO. This is an example of an approach that will provide advisory vertical guidance
to you. The light gray dashed line at the FAF (ACVOL) depicts the intercept of the advisory vertical path. The GNS 480 will
annunciate Lnav/Vnav when the approach is selected. This indicates that a vertical path is provided. It is not, however an Lnav/Vnav
approach, and does not have Lnav/Vnav minimums. The MDA of 640’ remains controlling in this case for a straight in landing.
The VDI will become active when ACVOL becomes the active waypoint, and the intercept of the path may be treated in the same
fashion as the LPV vertical path. Interim step down altitudes constraints will be met if you remain on the vertical path. The vertical
guidance will terminate at the runway end waypoint, and level off at the MDA should be anticipated. Although not depicted on this
approach, most advisory vertical guidance profiles are designed to intercept a VDP. You may either continue to the MAP at MDA or
initiate the missed approach climb when you reach MDA on the vertical path and/or the VDP.