Installation Instructions

GTN 6XX/7XX AML STC Installation Manual 190-01007-A3
Page 5-106 Rev. 4
5.7.9 GDL 88 Interface Check
When testing the GDL 88, the aircraft must be located outside and have an unobstructed view of the sky.
If the GDL 88 is installed and connected to the GTN, check the operation as follows:
1. Start all GTNs in Configuration Mode. See Section 5.5.
2. Go to the GDL 88 page in the External Systems page group.
3. Touch Diagnostics and then GPS/SBAS Data.
4. Verify that the GDL 88 is receiving valid position source data.
5. Verify that the status of the External PPS connection(s) is valid.
If a TAWS system is installed in addition to the GDL 88, check the operation as follows:
6. Go to the GDL 88 Discrete Input page under GDL 88 Diagnostics.
7. Verify the Audio Inhibit #1* discrete input indicates Active when the TAWS system is playing
audio, and Inactive otherwise. See Section 5.6.7.
5.7.10 Magnetic Compass Check
A compass swing should be carried out at completion of installation in accordance with AC 43.13-1B,
Chapter 12, Section 3, paragraph 12-37.
5.7.11 EMI/RFI Check
After installing the GTN and verifying that all interfaces to external equipment are working correctly, a
brief EMI/RFI check must be conducted. This check will verify that the GTN does not produce
unacceptable interference in other avionics systems, and other avionics systems do not produce
unacceptable interference in the GTN.
1. Start the aircraft engines and switch to aircraft power.
2. Turn on all avionics except the GTN.
3. With the GTN switched off, verify that all existing avionics systems are functioning properly.
4. Turn the GTN on and verify that all existing avionics systems continue to function properly.
5. Keep the GTN switched on and remove power from all other avionics systems.
NOTE
Removing power from systems interfaced to the GTN will cause the associated system
flags on the GTN to be displayed. This is normal behavior and does not constitute a test
failure.
6. Turn the display brightness level up to 100%.
7. Apply power to the other avionics systems one at a time and verify that the system functions
properly without any unacceptable interference caused by the GTN.
8. Wait for the system to begin functioning normally before applying power to the next system.
9. Once all of the systems are powered up, transmit on the COM over several different frequencies.
10. While transmitting, verify that the other aircraft systems function normally. If there is
interference, see Section 2.4.4.5 for ways to improve the situation.