Garmin GTN 6 series Maintenance Manual - page 41
190-01007-B1
GTN 6XX/7XX Part 27 AML STC Maintenance Manual
Rev. 1
Page 4-9
4.3.1.2
GPS/SBAS Related Alerts
Table 4-4. GPS/SBAS Alert Troubleshooting Guide
Alert Text
Possible Cause
Corrective Action
GPS RECEIVER - GPS
receiver has failed. Check
GPS coaxial for electrical
short.
A failure has been detected in the GPS/SBAS
receiver.
Verify that the center conductor is not shorted to the braid in the coaxial cable.
Contact Garmin Product Support for assistance.
GPS antenna cable may be shorted to
ground.
LOSS OF INTEGRITY (LOI) -
Verify GPS position with other
navigation equipment.
Improper antenna installation or coaxial
routing.
Check GPS antenna installation, connections, and cable routing. The GPS
antenna must be mounted on top of the
rotorcraft
.
Antenna shaded from satellites.
Make sure the
rotorcraft
is clear of hangars, buildings, trees, etc.
RF interference at 1575.42 MHz from VHF
COM.
Move GPS antenna further from the COM antenna. Add a 1575.42 MHz notch
filter in COM coaxial. Fix or replace the COM. Disconnect the ELT antenna
coaxial to check for possible re-radiation.
GPS NAVIGATION LOST -
Insufficient satellites. Use
other navigation source.
There is no GPS fix available or the system is
in dead reckoning mode.
Wait for GPS satellite geometry to improve.
Ensure the
rotorcraft
has a clear view of the sky.
GPS NAVIGATION LOST -
Erroneous position. Use other
navigation source.
An internal position warning has occurred.
RAIM has determined that the info from one or more GPS satellites may be in
error.
Ensure the
rotorcraft
has a clear view of the sky.
GPS RECEIVER - Low
internal clock battery.
The GTN has detected a low battery. Almanac
data may have been lost.
Replace the battery.
SEARCHING SKY - Search-
the-sky in progress.
The GTN is searching the sky for GPS
satellites.
Wait 20 minutes for the unit to complete the cycle or until the current position is
located.