Garmin GNC 420AW, Installation Manual

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400W Series Installation Manual Page 4-9
190-00356-02 Rev. G
4.5 Annunciators/Switches
4.5.1 Annunciators/Switches Function
NOTE
Installations in conformance with the requirements specified in this installation manual
may not require the use of any external annunciators, since all annunciations are provided
on the 400W Series front panel. Refer to Section 2.5.1 to determine whether or not
external annunciators are required.
4.5.1.1 Message Annunciate
When a new status message is available, the Message Annunciator flashes. When status messages remain
effective, the Message Annunciator illuminates.
4.5.1.2 Waypoint Annunciate
The waypoint annunciator output is driven in the following manner:
1. When the aircraft is within 10 seconds of reaching the turning point for a course change, the
waypoint annunciator flashes.
2. When the aircraft is in a turn, the waypoint annunciator illuminates and remains illuminated until
the turn is completed.
3. When a user arrival alarm is set and the aircraft is within the circle defined by the arrival alarm
radius at the arrival waypoint, the waypoint annunciator flashes for 10 seconds.
4. When a user arrival alarm is not set and the aircraft is within 10 seconds of reaching the arrival
waypoint, the waypoint annunciator flashes.
4.5.1.3 CDI SOURCE SELECT (GNS 430W Only)
This discrete input may be used to toggle between display of GPS and VOR/LOC/Glideslope information
on the MAIN external CDI/HSI. A momentary low on this pin performs the same function as pressing
the ‘CDI’ key on the GNS 430W bezel.
4.5.1.4 VLOC ANNUNCIATE (GNS 430W Only)
This annunciator output is driven when the unit is configured with a single CDI/HSI and the VOR/ILS
data is being displayed on the CDI/HSI. This output parallels the VLOC annunciator on the display.
4.5.1.5 GPS ANNUNCIATE (GNS 430W Only)
This annunciator output is driven when the unit is configured with a single CDI/HSI and the GPS data is
being displayed on the CDI/HSI. This output parallels the GPS annunciation on the display.
4.5.1.6 OBS MODE SELECT
This discrete input may be used to toggle between GPS OBS and GPS AUTO modes of operation. A
momentary low on this pin performs the same function as pressing the ‘OBS’ key on the 400W Series
unit.
4.5.1.7 OBS ANNUNCIATE
This annunciator output is driven to indicate GPS OBS mode of operation. This output is active when the
OBS or SUSP annunciation is on the display.
4.5.1.8 TERMINAL ANNUNCIATE
When performing approach navigation, the terminal annunciator is illuminated when operating within 30
nautical miles of the departure or arrival airport and the CDI scale is the equivalent or 1.0 nm or less.