Garmin GNC 300XL TSO - Manual (Page 87)

SECTION
5
ROUTE NAV
Turn Anticipation
During route operations, the CDI page is used to provide turn anticipation, next
desired track and waypoint arrival information to the pilot. The GNC 300XL’s turn
anticipation feature will smooth out the transition between adjacent route legs by pro-
viding CDI guidance along a curved path segment. This leg transition is based on the air-
craft’s actual ground speed and the difference between the course angle of the two legs.
The GNC 300XL will automatically sequence to the next leg when you are abeam the
‘active to’ waypoint on the curved transition segment, and the to/from indicator on the
CDI will flip momentarily. During the transition, the CDI display will be referenced to
the dotted line illustrated at the right. Turn anticipation will not be provided in the
following scenarios:
• Waypoint/fix crossing is a requirement of the approach, SID or STAR
you’re navigating.
• The GPS SEQ switch is in the HOLD position.
• Your current ground speed and the course angle between the two legs
require a bank angle greater than 25º (see right).
As you approach a route waypoint, the GNC 300XL’s external waypoint annunciator
will flash 15 seconds before the turn anticipation point, and the graphical CDI on the
CDI page will be replaced by a flashing ‘Next dtk xxxº’ prompt (and the desired track
readout on the map page will flash), indicating the desired track of the next route leg.
To use the turn anticipation feature, note the ‘Nxt dtk’ heading when the external
waypoint annunciator begins to flash, and start the turn when the annunciator glows
steadily (approximately 2 seconds before the turn anticipation point). Once you’ve
reached the turn anticipation point, the desired track (dtk) field on the CDI page will
change to display the course for the next leg. If you have not adjusted your HSI course
selector before the turn, the ‘Next dtk’ will continue to flash until you have reached the
midpoint of the turn. Please refer to your aircraft flight manual supplement for specific
turn anticipation instructions.
Since the approach select, STAR select and SID select pages relate to the GNC
300XL’s approach features, these pages and their functions are described in Section 6.
If the turn angle and your present speed will
require a bank angle that exceeds 25º, you’ll be
notified with a ‘Steep turn ahead’ message
approximately 90 seconds before arrival at the
active to waypoint.
As you approach a route waypoint, the graphical
CDI will be replaced by a flashing ‘Next dtk xxxº’
prompt indicating the desired track of the next leg.
When using the map page, the desired track read-
out will flash and indicate the dtk for the next leg.
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300xl manual 1/25/99 2:35 PM Page 77