Garmin GNS 430 Pilot's Manual & Reference page 56

NAV PAGES
2
Vertical Navigation
(VNAV)
GPS accuracy may be degraded by the U.S.
Department of Defense-imposed Selective
Availability (SA) program. With "SA" on, GPS
altitude may be in error by several hundred
meters. Errors of this magnitude may result in
fluctuations in the VSR readout on the default
NAV page.
48
8. The default profile utilizes a 400 foot-per-minute descent rate. To change the rate, rotate the
d
large right knob ( ) to highlight the "VS Profile" field and use the small (
right knobs to enter a new rate. Press
With the profi le set, the vertical speed required (VSR) is displayed on the vertical
navigation page. Expect the following to occur when using the vertical navigation feature:
• At one minute prior to reaching the initial descent point, a message "Approaching
VNAV Profile" occurs. The descent (or climb) angle will also lock to prevent chang-
es in speed from altering the profile.
• If selected, the vertical speed required (VSR) readout on the default NAV and map
pages will show the desired vertical speed to maintain the proper descent (or climb)
angle.
• At 500 feet above (or below, for a climb) the target altitude, an "Approaching Target
Altitude" message is provided. The VSR readout on the default NAV and map pages
is blanked out, at this point.
Vertical navigation messages can be turned on or off. (By default the messages are off.)
Turning the messages off allows you to keep the profi le settings you've entered previ-
ously, without having them generate messages when the feature isn't needed.
To disable/enable the vertical navigation (VNAV) messages:
1. Press to display the vertical navigation page options menu.
m
2. With "VNAV Messages On?" highlighted, press
you wish to turn them off, make sure "VNAV Messages Off?" is highlighted and press
a
) and large (
E when finished.
E . Or, if the messages are already on and
d
)
.
E