Garmin G1000 System Maintenance Manual page 336

14. Press the ALT key on the AFCS mode controller and verify that the 'ALT' annunciation is displayed
in green on PFD1 and PFD2 with an altitude reference equal to the aircraft altitude (within the nearest
20 feet).
15. Press the FD key and verify that the mode annunciations and command bars are removed from the
display.
8.2.3 Autopilot Clutch Overpower Check
The GFC 700 uses electronic torque limiting as well as mechanical slip clutches to limit
the maximum servo effort. When the system is on the ground, the electronic torque
limiting is removed, allowing manual checks of the slip-clutch settings.
1. Engage the Autopilot by pressing the AP key on the AFCS mode controller.
2. Manually overpower the autopilot clutches in pitch and roll. If the Autopilot clutches cannot be
overpowered, check the GSM 86 clutch cartridge. Refer to the servo installation drawing (listed in
Table 1-2) as applicable.
3. Actuate and hold PITCH TRIM switch in either the NOSE UP or NOSE DOWN direction to
disconnect the autopilot. While the trim is running, restrain the aircraft pitch trim wheel and verify
that the trim clutch can be overpowered. If it cannot be overpowered, check the GSM 86 clutch
cartridge. Refer to the pitch trim servo installation drawing listed in Table 1-2.
4. Engage the autopilot by pressing the AP key on the AFCS mode controller. Actuate and hold the
manual electric trim switch in either the up or down direction to disconnect the autopilot. Verify that
the trim wheel moves smoothly in both directions throughout the entire trim range during manual
electric trim operation. If the trim wheel hesitates, this may indicate that the pitch trim clutch is
slipping and proper clutch setting or clutch cartridge and cable tension should be verified. Refer to
the Super King Air 300 or B300 Maintenance Manual and Pitch Trim Servo Install drawing, listed in
Table 1-2, for clutch settings and cable tensions. If both clutch setting and cable tension are within
tolerance, check the aircraft pitch trim system for excessive friction. Refer to the Super King Air 300
or B300 Maintenance Manual listed in Table 1-2.
8.2.4 Manual Electric Pitch Trim Speed Check
1. Run MANUAL ELECTRIC PITCH TRIM in one direction until it runs against the mechanical stop.
2. Run the trim in the opposite direction, and using a stop watch or equivalent device, time the trim
speed to the opposite mechanical stop. Verify the elapsed time for full travel measures 13 ± 3
seconds.
Page 8-12
Revision 4
NOTE
G1000 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
190-00716-01