Equipment Installation Manual,
GDC31 Roll Steering Converter
EQUIPMENT CHECKOUT
The GDC31 provides conversion of Serial data from a GPS receiver into a steering signal connected to
the autopilot heading channel through switching controlled by the HDG/GPS mode selector switch.
There are no other operator controls associated with the GDC31 unit.
The GPS receiver and the Autopilot must both be operational in order to perform this functional checkout.
Ground Functional Test
1. Insure that all control surfaces are clear and that the control wheel is centered in roll.
2. Apply power to the GPS Receiver and Autopilot.
3. Set the HDG/GPS Mode selector to HDG.
4. On the HSI, center the heading bug.
5. Engage the autopilot in Heading Mode.
6. Operate the heading bug; observe that the control wheel turns left and right in response to the
heading bug operation.
7. Center the control wheel using the heading bug.
8. Create and activate a flight plan in the GPS unit according to existing maintenance and / or flight
manual instructions.
9. Place the HDG/GPS Mode selector in the GPS position. Observe GPS illuminates and is not
blinking.
10. Remove power from the GPS receiver.
11. Observe that the GPS mode annunciator begins to blink within 15 seconds.
12. Verify that the control wheel centers once the GPS mode annunciator blinks.
13. Disengage the autopilot.
14. Ground test complete. Secure aircraft power.
Flight Functional Test
1. Set the HDG/GPS Mode selector to HDG.
2. On the HSI, center the heading bug.
3. Engage the autopilot in Heading Mode.
4. Operate the heading bug; observe that the control wheel turns left and right in response to the
heading bug operation.
5. Center the heading bug.
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