Garmin GTN 6 series Maintenance Manual page 110

7.4.3.2 Sandel SN3308 Interface Check
If a Sandel EHSI has been connected to the GTN, the interface should be verified as described in one of the
following sections, as appropriate for the installation.
7.4.3.2.1 One GTN/One SN3308
1. Cycle power to the GTN and acknowledge the prompts until it gets to the Instrument Panel Self-
Test page (see Section 6.1.1).
2. Ensure that the SN3308 is receiving valid heading.
NOTE
The Vertical Deviation Indication will not be displayed unless the SN3308 is receiving
valid heading.
3. While the GTN is displaying the Instrument Panel Self-Test page, verify that the SN3308 is
displaying the following data from the GPS source.

Course Deviation: Half-scale left deviation, TO indication, flag pulled
 Vertical Deviation: Half-scale up deviation, flag pulled
 Active Waypoint: GARMN
4. On the GTN verify that an OBS value is displayed (and not dashed out).
5. Acknowledge the self-test on the GTN by touching the Continue key.
6. Select VLOC on the GTN and verify that the SN3308 displays NAV 1 or NAV 2 (depending on the
GTN navigation source configuration).
7. Using a VOR test set verify that the CDI deviation on the SN3308 is displayed correctly.
System Maintenance Manual GTN 6XX/7XX Part 23 AML STC
Page 7-14
190-01007-A1
Rev. 6