System Maintenance Manual GTN 6XX/7XX Part 23 AML STC
190-01007-A1
Page 4-2
Rev. 5
4.3 Maintenance Intervals
Table 4-1. Periodic Maintenance
Item
Description/Procedure
Interval
Equipment Removal
and Replacement
Removal and replacement of the following items. See Section 6
of this document for instructions.
• GTN 6XX/7XX or GMA 35 units
• NAV antenna cable splitter
• NAV antenna cable diplexer
• Fan
On Condition
Cleaning the Front
Panel
The front bezel, keypad, and display can be cleaned with a soft
cotton cloth dampened with clean water. DO NOT use any
chemical-cleaning agents. Care should be taken to avoid
scratching the surface of the display.
On Condition
Display Backlight
The display backlight LEDs are rated by the manufacturer as
having a usable life of at least 36,000 hours. This life may be
more or less than the rated time depending on the operating
conditions of the GTN. Over time, the backlight lamp may dim
and the display may not perform as well in direct sunlight
conditions. The user must determine by observation when the
display brightness is not suitable for its intended use. Contact the
Garmin factory repair station when the backlight lamp requires
service.
On Condition
Battery
Replacement
The GTN has an internal keep-alive battery that will last about 10
years. The battery is used for GPS system information. Regular
planned replacement is not necessary. The GTN will display a
‘low battery’ message when replacement is required. Once the
low battery message is displayed, the battery should be replaced
within 1 to 2 months.
If the battery is not replaced and becomes totally discharged, the
GTN unit will remain fully operational, but the GPS signal
acquisition time may be increased. There is no loss of function or
accuracy of the GTN unit with a dead battery.
The battery must be replaced by the Garmin factory repair
station or factory authorized repair station.
On Condition
Test - Bonding
Check
Perform an electrical bonding check of the GTN and GMA (if
installed) per Section 4.5.
Every 10
years or 2000
flight hours,
whichever
comes first.
Test TVS Lightning
Protection
The GTN #1 main power input will have a TVS located at the
LRU, for
IFR
non-metallic aircraft only
. The TVS must be
checked or replaced in accordance with Section 4.6.1.
24 Calendar
Months
