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4-5190-01182-01 Rev. A
Garmin GNC 255A/255B Pilot’s Guide
Message Description Action
COOLING FAN -
The cooling fan has
failed.
The GTN cooling fan is
powered, but it is not
turning at the desired
RPM.
Decrease cabin temperature and
increase cabin airflow (especially
near the GTN) to prevent damage
to the unit. Contact dealer for
service.
DISPLAY -
Display board
needs service.
The display board is
indicating that it needs
service.
Contact dealer for service.
GLIDESLOPE -
Glideslope receiver
needs service.
The glideslope board is
indicating that it needs
service. The glideslope
board may continue to
function.
Verify glideslope deviation
indications with another source
and crosscheck final approach
fix crossing altitude. If another
glideslope source is not available
for verification, fly a GPS based
approach. Contact dealer for
service.
GLIDESLOPE -
Glideslope receiver
has failed.
The glideslope board
is not communicating
property with the
system.
Fly an approach that does not use
the glideslope receiver (VOR, LOC,
GPS). Contact dealer for service.
POWER ALERT -
Unit will shut down
if power switch
is not restored
immediately.
Power has been
removed from the unit.
Re-apply power to the unit.
REMOTE KEY
STUCK -
Com push-to-talk
key is stuck.
The Push To Talk key/
switch has been in
pressed position for
at least 30 seconds.
This input will now be
ignored and the com
radio will no longer
transmit.
Verify the Push To Talk key/switch
is not stuck. Contact dealer for
service if this message persists.