DeX Operations Manual V. 2.1
Page 37
To activate a VILS procedure use the approach feather tab from the airport data screen
(see page 31)
of the desired destination airport and select the “VIRTUAL ILS” for
the desired runway, then choose Activate Approach. VILS procedures can either
operate in FIXED or VECTORS mode.
Fixed mode will set up a flight plan to an initial approach fix (IAF) located 5 nautical
miles out from the Final Approach fix, which is nominally 5 miles out. The aircraft will
then be expected to fly to this fixed location, intercept the “virtual localizer” (extended
runway centerline) and descend towards the runway, following the selected glideslope.
Vectors mode sets up the flight plan to a “floating” IAF, located between 1 and 10
miles outbound from the FAF. This mode works much like being vectored to intercept
the localizer. The course line is drawn from current location to the intercept point along
the runway centerline, then along the centerline to the FAF, then along the centerline to
the runway endpoint, with glideslope like guidance along the way.
The approach setup screen allows one to vary the glideslope angle (3 degrees is the
typical glideslope), and also allows one to vary the distance from the runway endpoint
to the FAF. Think of the FAF as the outer marker. In a real ILS, one should be fully
configured for landing at the FAF, and simply follow the glideslope / localizer to the
runway endpoint in a stabilized approach from that point.
Tap OK in this screen to create the VILS flight plan and enable the approach. To cancel
the VILS, clear the flight plan using the flight plan screen.
The
easiest way to use the Virtual glideslope
approach is to select
“ENABLE
AUTO VIRTUAL ILS
” in the Airport tab of the View Settings screen. With this
selected, the VILS for your destination airport will automatically be selected
based on the runway you appear to be approaching. Note that the auto
selection process “locks” at 3 miles distance from the airport, to prevent
confusion at large airports with multiple runways.
The rocker switch may be used to accurately choose the desired approach after
a procedure is highlighted in the list box if using the unit in turbulence.
VNAV Concepts
The basic concept of VNAV is the
TARGET ALTITUDE
. Anywhere Map allows a
target altitude to be assigned to any waypoint in a flight plan. If a target altitude is
active for a waypoint, the software will compute the rate of climb or descent necessary
to reach that altitude, based on the time-to-fix and altitude difference. When the next
waypoint has a target altitude associated with it, the software will draw an up or down
arrow next to the fix name at the top of the screen, indicating that a climb or descent is
required.
Tap >Windows >VNAV info to enable this powerful tool and the target rate of climb or
descent will be shown in the lower right corner of the map screen. The value shown is
not the current rate of climb/descent, but rather the rate of climb/descent NEEDED to
reach the target altitude concurrently with reaching the fix.
If the aircraft’s current rate of climb or descent is greater than 200 feet per minute, a
VNAV target altitude arc will appear in front of the aircraft at the point in space where
