System Maintenance Manual

Page 4-26 G1000/GFC700 System Maintenance Manual – C90A/C90GT/C90GTi King Air
Revision G 190-00682-01
4. Attach a socket to a calibrated torque wrench of appropriate range and place on top of the fixture
capstan. Adjust the wrench support fixture so that it contacts the handle in the appropriate
location.
5. Connect a 2 Amp, 24 V, DC power supply to the fixture.
6. Place the solenoid switch to "on" and move the direction switch to the clockwise or counter-
clockwise position. Allow the clutch to rotate at least one revolution in each direction (note: the
capstan itself is fixed.)
7. Observe the torque reading for at least two full revolutions in each direction. Ensure the
minimum and maximum torque readings are within the tolerance specified.
8. If the minimum and maximum torque values are within the specified range in Table 4-11, the
GSM slip clutch is acceptable. Reinstall the GSM 85A or GSM 86 servo gearbox per Section
6.12.
9. If the minimum and maximum torque values are not within the specified range in Table 4-11, the
GSM 86 slip clutch cartridge must be replaced or the GSM 85A must be adjusted.
10. For GSM 85A only: If adjustment is required, remove cotter pin and adjust the nut on the capstan
as needed to obtain the torque value listed in Table 4-11, as shown on the torque wrench.
Position the nut to align with holes in the capstan shaft and install a new cotter pin.
11. When finished, remove the fixture cable, and then remove the servo gearbox from the fixture.
12. Install the GSM 85A or GSM 86 servo gearbox per Section 6.12.
Table 4-11. Slip Clutch Torque Settings
Servo Pitch Trim* Pitch Yaw Roll
GSM 85A Setting 49 +/-6 in-lbs* 88 +/-10 in-lbs 83 +/-10 in-lbs 73 +/-9 in-lbs
GSM 86 Setting 45 +/-13 in-lbs* 90+/-24 in-lbs 90 +/-18 in-lbs 72+/-21 in-lbs
*Valid with continuous travel servo gearbox only
4.9.4 Servo Current Display Check
To ensure proper operation during this test, it is necessary to remove power from the aircraft prior to
starting.
1. Press and hold the enter button on PFD1, and restore power to the aircraft.
2. With PFD1 in Configuration Mode, go to the GFC Page Group and select the GFC STATUS page
using the FMS knobs.