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System Operation
3-87
GNS-XL Flight Management System
Rev. 0
Oct/96
Figure 3-141
#TOD
8000
FUELR
Descent Reference
Wpt
126
KLAX
Cruise Altitude FL210
Vertical Constraint
FL180B
16500 PLAN CROSSING
Programmed FPA 3.0
CIVET
14000A
Vertical Constraint
As shown, FUELR is the Descent Reference Waypoint
that establishes #TOD. Because the programmed
FPA allows for a vertical descent that meets the
vertical constraints at CIVET, FUELR remains the
Descent Reference Waypoint.
#TOD
8000
FUELR
Descent Reference
Wpt
126
KLAX
Cruise Altitude FL210
FL180B
14000 PLAN CROSSING
Default FPA 3.0
Programmed FPA 1.0
CIVET Descent Reference Wpt
14000A
In this case, since the programmed FPA at FUELR is
too shallow to meet the vertical constraints at CIVET,
the system reassigns CIVET at the Descent Reference
Waypoint, using the default FPA to compute #TOD.
Top of Descent and Descent Reference Waypoint