Garmin G500, Instructions Manual

Page: 275 / 334

G500/G600 PFD/MFD System 190-00601-00 Rev. M
Instructions for Continued Airworthiness Page 6 of 13
2.5.9 Mid-Continent Instruments Attitude Indicator Models 4300-4( ), or 4200-( ) with MD420
If a Mid-Continent Instruments Attitude Indicator is installed as part of the G500/G600 AML STC, the
battery pack must be tested by one of the following means:
1. Manual:
a. Disconnect the battery pack from the Attitude Indicator.
b. Ensure the battery pack is completely charged and at or near room temperature.
c. Connect the battery to a load of 90 ohms (rated for 10 watts) for 60 minutes while
monitoring the battery voltage level.
i. If the battery voltage is at or above 15.0 volts while under load at the end of the
60 minute test, the battery may be recharged in accordance with the
Mid-Continent Instruments Installation Manual and re-installed in the aircraft.
ii. If the battery voltage is below 15.0 volts while under load at the end of the 60
minute test the battery must be replaced.
2. Automatic:
a. Use the Mid-Continent Instruments Battery Charger/Tester P/N 36029 to test the
battery.
i. If the time required for discharge is 60 minutes or greater, the battery may be
recharged in accordance with the Mid-Continent Instruments Installation Manual
and re-installed in the aircraft.
ii. If the time required for discharge is less than 60 minutes, the battery must be
replaced.
****WARNING****
The battery may be permanently damaged if it is left in a discharged state.
Recharge a discharged battery as soon as possible and
maintain with a float charge for maximum battery life.
Within the preceding 12 calendar months, proper operation of the attitude instrument must be verified
with the following procedure:
1. Apply aircraft power to the unit and verify that the invalid flag is removed from view and the
STBY PWR indicator is not illuminated.
2. Remove aircraft power from the unit and verify that the invalid flag is not visible and the STBY
PWR indicator is flashing.
3. Press the STBY PWR button and verify that the invalid flag is not visible and the STBY PWR
indicator is not flashing.
4. Press the STBY PWR button a second time and verify that the invalid flag is displayed.
Otherwise maintenance of the Mid-
Continent Instruments attitude indicator is ‘on condition’ only.
2.5.10 Electrical Bonding Test
G500/G600 LRU electrical bonding must be tested every 2000 flight hours or ten (10) years, whichever
is first. During the test, any cables normally attached to the LRU must be disconnected from the LRU. If
measured resistance is greater than applicable values in the following table, bonding must be improved
to meet applicable requirements for a new installation in accordance with section 3.8 of the G500/G600
AML STC Installation Manual.
LRU Metallic Aircraft Non-Metallic Aircraft
GDU 620
– Display Unit
40 m
Ω (to instrument panel) 40 mΩ (to instrument panel)
GSU 75(B)
– Air Data and Attitude
Heading Reference System
(ADAHRS)
20 m
Ω (to aircraft ground
plane)
20 m
Ω (to instrument panel)