System Maintenance Manual

Page 8-2 G1000/GFC700 System Maintenance Manual – C90A/C90GT/C90GTi King Air
Revision G 190-00682-01
8.1 Backup Path System Testing
This final checkout tests various secondary communications paths in the G1000 to ensure that the paths
function correctly. Additional aircraft systems checks are also performed in this section. Perform the
following steps and verify the results of each test.
8.1.1 GPS Failure Test
NOTE
Depending upon aircraft status and c
onfiguration, various other messages and
alerts may be present on GDUs during the failure tests.
Step
Desired Result
Single GPS Failure Conditions:
1. Ensure GPS satellites are acquired.
2. Place a shroud over the GPS antenna for
GIA 1 to prevent signal reception. Verify
loss of signal on MFD AUX page 4.
3. Check for desired results.
4. Remove shroud from the GIA 1 GPS
antenna and allow system to re-acquire
satellites.
5. Place a shroud over the GPS antenna for
GIA 2 to prevent signal reception. Verify
loss of signal on MFD AUX page 4.
6. Check for desired results.
7. Remove shroud from the GIA 2 GPS
antenna.
GPS Failure – For each of the specified GPS failure
conditions, the following shall remain valid on the
PFD throughout the procedure:
• Attitude and Heading from AHRS.
• Airspeed, Altitude, Vertical Speed, and OAT from
Air Data Computer.
• GPS Course Deviation Indicator remains valid on
PFD.
For a GIA1 GPS Failure, an amber BOTH ON
GPS2 is displayed on PFD 1 and PFD 2.
For a GIA2 GPS Failure, an amber BOTH ON
GPS1 is displayed on PFD 1 and PFD 2.
Dual GPS Failure Conditions:
1. Ensure GPS satellites are acquired.
2. Cover both GPS antennas. Verify loss of
signal on MFD AUX page 4.
3. Check for desired results.
4. Remove shrouds from GPS antennas.
5. Allow both receivers to re-acquire satellite
signals before continuing.
Dual GPS Failure - For a dual GPS failure, the
following shall occur:
• GPS CDI flags LOI on both PFDs.
• Attitude and Heading remain valid from both
AHRS on both PFDs.
• Airspeed, Altitude, Vertical Speed, and OAT
remain valid from both Air Data Computers on
both PFDs.
• No GPS Position appears on MFD Map.
• TAWS N/A aural alert & annunciation given.
When GPS satellites are re-acquired, verify that the
INTEG OK annunciation is given on the HSI in white
for a brief period of time then disappears.
After ~10 seconds of stable GPS position
reacquisition, verify the TAWS AVAILABLE aural
alert is given.
Verify that the system returns to normal navigation
mode (GPS CDI restored, DR annunciation
removed, & GPS data magenta).