Garmin GFC 500 Maintenance Manual page 35

9.3.1 Servo Tests
If a servo has been removed and reinstalled (or replaced), perform the following steps.
1. Load software as shown in Section 8.1.
2. Power the GFC 500 in normal mode.
3. Complete Pre-Flight Test (PFT) as shown in Section 9.2.
4. Proceed to the sub-section below as appropriate for the servo that has been replaced.
9.3.1.1 Roll Servo Functional Check
1. Verify that the steps in Section 9.3.1 have been completed.
2. Center the heading bug on the aircraft heading.
3. Engage the autopilot by pressing the AP button on the GMC 507.
4. Verify that the roll control is restricted from free movement.
5. Press the HDG button to engage roll mode.
6. Rotate the heading bug to the left of the current aircraft heading.
7. Ensure that the command bars indicate a left roll and that the servo drives the flight
controls to the left.
8. Rotate the heading bug to the right of the current aircraft heading.
9. Ensure that the command bars indicate a right roll and that the servo drives the flight
controls to the right.
10. Firmly grasp the control wheel and press the AP DISC/TRIM INT switch on the pilot's
flight controls.
11. Verify that the autopilot disconnects and the roll control moves freely.
9.3.1.2 Pitch Servo Functional Check
1. Verify that the steps in Section 9.3.1 have been completed.
2. Center the elevator controls approximately mid-travel.
3. Engage the autopilot by pressing the AP button on the GMC 507.
4. Verify that the pitch control is restricted from free movement.
5. Rotate the NOSE UP/DN thumbwheel on the GMC 507 UP three clicks.
6. Ensure that the flight director command bars indicate a pitch up and that the pitch servo
drives the controls in a nose up direction. NOTE: In some aircraft, some assistance may
be needed to drive the flight controls against any counterweight or springs.
7. Rotate the NOSE UP/DN thumbwheel on the GMC 507 DN three clicks.
8. Apply continuous forward pressure on the pitch control in a nose down direction.
9. Ensure that the pitch trim (if installed) begins running in the nose up direction.
10. Apply continuous aft pressure to the flight controls in a nose up direction.
11. Ensure that the pitch trim (if installed) begins running in the nose down direction.
12. Rotate the NOSE UP/DN thumbwheel on the GMC 507 DN three clicks.
GFC 500 Autopilot with ESP Part 23 AML STC Maintenance Manual
190-02291-01
Page 28
Revision 1