____________________________________________________________________
Page 7-28
G1000 System Maintenance Manual
Rev. A
190-00903-00
18.
Press the FD key on the GMC 710 twice to deactivate the Go Around mode and reset the
flight director. Green “PIT” and “ROL” annunciations and the flight director command bars
will be visible on the PFD.
19.
Center the trim wheel if it is not already centered.
20.
Press the AP key to engage the autopilot.
21.
Press the CWS button and verify there is no residual force on the control wheel for the pitch
axis.
22.
Disengage the autopilot by pressing the AP DISC switch.
Autopilot Clutch Overpower Check
NOTE
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. The clutch overpower check is not necessary if the GSM 85(A) servo
mount was not changed or serviced.
1.
Engage the Autopilot by pressing the AP key on the GMC 710.
2.
Apply force to the control yoke to determine if the Autopilot clutches can be overpowered in
pitch and roll. Overpowered means that the control surfaces can be moved by applying force
to the control wheel or the rudder pedals against the resistance of the engaged Autopilot. If
the Autopilot clutches cannot be overpowered, check the servo clutch torque settings.
3.
Apply force to the rudder pedals to determine if the Autopilot clutch can be overpower in
yaw. If the Autopilot clutch cannot be overpowered, check the servo clutch torque settings.
4.
Actuate the MET switch (this causes an Autopilot disconnect). While the trim is running,
grasp the aircraft pitch trim wheel and verify that the trim clutch can be overpowered by
preventing the trim wheel from moving. If it cannot be overpowered, check the trim servo
clutch torque setting. Verify also that the trim wheel moves smoothly in both directions
throughout the entire trim range during MET operation. If the trim wheel hesitates
excessively (more than 2 seconds without motion), this may indicate that the pitch trim
clutch is slipping. First verify proper clutch setting and cable tension. If both clutch setting
and cable tension are within tolerance, check the aircraft pitch trim system for excessive
friction.
Manual Electric Trim Speed Check
1.
Run MET in one direction until it runs against the stop.
2.
Using a stop watch or equivalent device, time the trim speed from one end of travel to the
opposite stop. The elapsed time should measure 20
±
5 seconds for each direction.
Autopilot Operation Checks
Push the HDG knob in to synchronize the heading bug to the present aircraft heading on the HSI.
1.
Engage the Autopilot and Yaw Damper by pressing the AP key on the GMC 710.
2.
Select Heading mode by pressing the HDG key on the MFD. The command bars should be
level and the control wheel should be stationary (very slow movement acceptable, due to the
aircraft not being perfectly level).
