Garmin GPS 400 Pilot's Manual And Reference page 44

NAV PAGES
1 5
PROCEDURES
Vertical Navigation
Approach Examples
(VNAV)
The satellite status page also indicates the accuracy of the position fix, using
Estimated Position Error (EPE) and Dilution of Precision (DOP) figures. DOP
measures satellite geometry quality (i.e., number of satellites received and where
they are relative to each other) on a scale from one to ten. The lowest numbers are
the best accuracy and the highest numbers are the worst. EPE uses DOP and
other factors to calculate a horizontal position error, in feet or meters.
Vertical Navigation Page
The GPS 400's vertical navigation page (the last NAV page) allows you to create
a three-dimensional profile which guides you from your present position and
altitude to a final (target) altitude at a specified location. This is helpful when you'd
like to descend to a certain altitude near an airport or climb to an altitude before
reaching a route or direct-to waypoint. Once the profile is defined, message alerts
and additional data on the default NAV and map pages will keep you informed of
your progress.
Target Altitude
Target
Distance
Vertical Speed
Desired
To use the vertical navigation features, your ground speed must be
greater than 35 knots and you must be navigating to a direct-to
destination or using a flight plan.
Altitude Reference
(AGL or MSL)
Target Reference
Vertical Speed
Required
Sixth Page
in NAV group