System Maintenance Manual

G1000/GFC700 System Maintenance Manual – C90A/C90GT/C90GTi King Air Page 5-31
190-00682-01 Revision G
5.6.1 General Troubleshooting
The following annunciations may appear in the AFCS Annunciation field:
Table 5-3. AFCS Annunciation Troubleshooting
Annunciation Condition Resolution
AFCS System
Failure
• Confirm AFCS Servo circuit breaker IN
• Ensure that the G1000 system is in proper working order.
Check specifically for proper operation of the:
 GIA 63 Integrated Avionics Units
 GRS 77 AHRS Units
 GDC 74B Air Data Computers
 All GSA 80 and GSA 81 Servos
• Check that no red X’s are present on the MFD and PFD
displays.
• Check that no related alert messages are present on the
PFD displays (press the ALERTS softkey).
• Go to the AUX SYSTEM STATUS page on the MFD and
verify that all LRUs have a ‘green’ check (see Section 5).
• In Configuration mode, review the GFC 700 equipment
status, software, and certification gains.
• Reload software, configuration, and certification gains to the
GIAs and GSA 80 and GSA 81 servos.
• Check the GFC Status page for additional GFC 700 system
information.
• Review the fault and assert logs for the GIAs and servos
(see Section 5.6.4)
• Isolate the fault to an LRU. Replace this LRU and confirm
the resolution of the annunciation.
Pitch Axis Failure
• Check the AUX – SYSTEM STATUS page to see if the
servo is online (green check).
• Check that the affected servo is receiving power.
• Check the servo wiring and connector.
• For pitch trim, check pitch trim switch operation to verify
switch contacts are not stuck.
• If failure condition still exists, remove and replace the
affected servo.
Pitch Trim Axis
Failure
Yaw Axis Failure
Roll Axis Failure
AHRS Monitor
Failure
• If the AHRS inputs have been determined to be
“unreasonable” while the AP is engaged, in air, this message
will be displayed until AHRS inputs are determined
reasonable for 5 seconds.
Elevator Mis-Trim
Down
• If elevator mistrim annunciations persist, check the pitch and
pitch trim servos for proper operation. Verify that the servo
is online at the AUX – SYSTEM STATUS page.
• Check the servo wiring and connectors. Ensure the servo is
receiving power.
• Check the aircraft control adjustments.
• If mistrim condition still exists, remove and replace the
affected servo.
Elevator Mis-Trim
Up