G900X/G950 Installation and Maintenance Manual – Troubleshooting
Page D-5
190-00719-00
Revision D
System Annunciation Troubleshooting (continued)
Annunciation
Associated
LRU
Solution
ATTITUDE FAIL
GRS 77 #1
or
Optional #2
•
Ensure that a cell phone or a device using cell
phone technology is not turned on (even in a
monitoring state) in the cabin.
•
Check PFD Alert Window for PFD, MFD or GRS
configuration, software or failed data path error
messages. Correct any errors before proceeding.
•
For an attitude failure while parked, check the
following –
•
Is the aircraft stationary if GPS is not available?
Aircraft movement (rocking the wings or moving
the tail) may cause the attitude and heading to
fail if it believes the aircraft is in motion without
GPS input.
•
Check if the GPS has acquired at least four
satellites, has a 3D navigation solution, and a
DOP of less than 5.0.
•
Check for metal objects (tool boxes, power carts,
nearby large steel structures, etc.) around the
aircraft that could be interfering with the
magnetometer.
•
Cycle GRS 77 power to restart initialization.
•
Check the GRS 77 connecter for security and that
proper wire harness strain relief is provided.
•
Check the GRS 77 is fastened down tightly in its
mounting rack and that the mounting rack is not
loose (CAUTION - do not loosen the mounting rack
hardware to the airframe shelf or the aircraft will
need to be re-leveled and the PITCH/ROLL
OFFSET procedure performed).
•
Perform an Engine Run-Up Test to check if engine
vibration is causing the GRS 77 to go offline.
•
Replace GRS 77.
•
If problem persists replace the GRS 77
configuration module.
•
Contact Garmin Aviation Product Support if
condition continues after replacing the GRS 77 and
config module for additional assistance.
