Garmin GNC 420(A) Pilot's Manual & Reference page 230

SECTION 13 – MESSAGES,
ABBREVIATIONS, & NAV TERMS
Message
Approaching VNAV
profile
Arrival at waypoint
[waypoint name]
Cannot navigate
locked FPL
Can't change an active
waypoint
Can't delete an active
or FPL waypoint
Check unit cooling
COM has failed
COM is not responding
COM needs service
COM push-to-talk key
stuck
COM remote transfer
key is stuck
COM transfer key
stuck
13-2
The aircraft is within one minute of reaching the initial Vertical Navigation descent, or climb,
point.
The aircraft is within the arrival alarm circle for the indicated waypoint. The size of the arrival
alarm circle is defined from the 'CDI/alarms' menu option on the Setup 1 Page.
The pilot has attempted to navigate a flight plan (FPL) with one or more locked waypoints. A
waypoint can be 'locked' when the NavData Card is replaced and the waypoint(s) does not
exist in the new database.
An attempt has been made to modify the position of the active 'to' or 'from' waypoint.
The GNC 420 does not allow modifications to user waypoints currently being utilized for
navigation guidance.
An attempt has been made to delete the active 'to' or 'from' waypoint. The GNC 420 does
not allow the deletion of user waypoints currently being utilized for navigation guidance.
The GNC 420 has detected excessive display backlighting temperature. The backlighting has
been automatically dimmed to reduce the temperature. Check for adequate ventilation or
check cooling air flow. Contact a Garmin dealer for assistance.
The GNC 420 has detected a failure in its communications transceiver. The COM transceiver
is not available and the unit should be returned to a Garmin dealer for service.
Internal system-to-system communication between the main processor and the COM
transceiver has failed. Operational status of the COM transceiver is unknown and the unit
should be returned to a Garmin dealer for service.
The GNC 420 has detected a failure in its communications transceiver. The COM transceiver
may still be usable, but the unit should be returned (at earliest convenience) to a Garmin
dealer for service.
The external push-to-talk (PTT) switch is stuck in the enabled (or pressed) state. Try pressing
the PTT switch again to cycle its operation. If the message persists, contact a Garmin dealer
for assistance.
The remote COM transfer switch is stuck in the enabled (or pressed) state. Try pressing the
switch again to cycle its operation. If the message persists, contact a Garmin dealer for
assistance.
The COM Flip-flop Key is stuck in the enabled (or pressed) state. Try pressing the COM Flip-
flop Key again to cycle its operation. If the message persists, contact a Garmin dealer for
assistance.
GNC 420(A) Pilot's Guide and Reference
Description
190-00140-20 Rev. K