To activate the VNAV function:
1. Review the calculated vertical speed. If the calculated
speed does not fit within the performance guidelines of your
aircraft, manually enter the appropriate speed in the ‘At’
field and press
E
.
2. Highlight the ‘Vnav’ field.
3. Press the
E
key.
4. Use the arrow keypad to select the’On’ setting.
5. Press
E
.
The VNAV status at the bottom of the page will
change from ‘Enter Profile’ to ‘Begin In _____’, indicat-
ing the time remaining to begin the descent. Once you
a re less than 15 seconds from the starting point of the
descent, you’ll be informed with a ‘Start Altitude
Change’ message. If the maneuver has already start e d ,
the status field will display a ‘Navigating’ status.
While the VNAV function is active, the vertical naviga-
tion page will provide a continuous display of the re c-
ommended altitude you should be at (the ‘From’ fie l d )
and vertical speed re q u i red (the ‘At’ field) to complete
the maneuver.
When the recommended altitude is within 1,000 feet
of the final altitude, you’ll be informed with a ‘Final
Altitude Alert’ message. The recommended altitude dur-
ing any active VNAV maneuver is also displayed at the
bottom right of the Navigation Page.
The VNAV function will be cancelled automatically if
the active route or GOTO is changed in any way (e.g.,
performing an on-route GOTO or adding a waypoint to
a route). Whenever this happens, you’ll be inform e d
with a ‘VNAV Cancelled’ message. If your current speed
does not exceed 35 knots, or a route waypoint that has
already been past is selected, the status line will display
‘Invalid Profile’. If there is no active GOTO or route, the
status field will display ‘No Active Waypoint’.
59
E6-B Menu
VNAV
The ‘Begin In’ field
indicates the time
remaining before
you should begin
your descent.
Whenever the active
route is modified in
any way, the VNAV
will automatically
be cancelled.
gps 90 manual 8/6/98 10:01 AM Page 59
