GNS 430 Pilot’s Guide and Reference
11-7
SECTION 11
TERRAIN
11.3 TERRAIN ALERTS
TERRAIN alerts are issued when flight conditions
meet parameters that are set within the TERRAIN system
software algorithms. When an alert is issued, visual
annunciations are displayed. Annunciations appear in
a dedicated field in the lower left corner of the display
(Figure 11-5).
Figure 11-5 TERRAIN Annunciation and Pop-up Alerts
TERRAIN
Annunciation Field
Pop-up TERRAIN Alert
Pop-up Alerts
On any page except the TERRAIN Page, when a terrain
or obstacle alert is issued, a pop-up window is displayed
with the appropriate alert (Figure 11-5).
To acknowledge the pop-up alert and
return to the currently viewed page:
Press the
CLR
Key.
To acknowledge the pop-up alert and
quickly display the TERRAIN Page:
Press the
ENT
Key.
Forward Looking Terrain Avoidance
The Forward Looking Terrain Avoidance alert, or
FLTA, is used by the TERRAIN system and is composed
of two elements:
• Reduced Required Terrain Clearance (RTC)
Avoidance - Provides alerts when the aircraft
flight path is above terrain, yet is projected to
come within minimum clearance values outlined
in Table 11-3. When an RTC alert is issued, a
potential impact point (Section 3.5) is displayed
on the TERRAIN Page.
• Imminent Terrain Impact (ITI) Avoidance
- Provides alerts when the aircraft is below the
elevation of a terrain cell in the aircraft’s projected
path. ITI alerts are accompanied by a potential
impact point displayed on the TERRAIN Page.
The alert is given when the projected vertical
flight path is calculated to come within minimum
clearance altitudes in the Table 11-3.
TERRAIN Phase of Flight Level Flight Descending
Enroute
700 feet
500 feet
Terminal
350 feet
300 feet
Approach
150 feet
100 feet
Departure
100 feet
100 feet
Table 11-3 Minimum Terrain and Obstacle Clearance Values for
FLTA Alerts
NOTE: See the TERRAIN Phase of Flight definition
in Section 11.2.
During the final approach phase of flight, RTC/ITI
alerts are automatically inhibited when the aircraft is
below 200 feet AGL while within 0.5 nm of the approach
runway or is below 125 feet AGL while within 1 nm of
the threshold.
Summary of Contents for GNS 430
Page 1: ...GNS 430 430A Pilot s Guide and Reference...
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Page 28: ...GNS 430 Pilot s Guide and Reference 1 20 SECTION 1 INTRODUCTION Blank Page...
Page 82: ...GNS 430 Pilot s Guide and Reference 5 16 SECTION 5 FLIGHT PLANS Blank Page...
Page 116: ...GNS 430 Pilot s Guide and Reference SECTION 6 PROCEDURES 6 34 Blank Page...
Page 154: ...GNS 430 Pilot s Guide and Reference 8 14 SECTION 8 NRST PAGES Blank Page...
Page 220: ...GNS 430 Pilot s Guide and Reference APPENDIX B SPECIFICATIONS B 2 Blank Page...
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