190-01115-01
G3X/G3X Touch Installation Manual - Maintenance
Rev. AC
Page 36-3
36.1.4 Transponder
All GTX 35R/45R/335/345 transponders, and GTX 23ES/33/33ES/330/330ES transponders with software
version 8.00 or later are compliant with RTCA/DO-181D, which specifies that the selection of transponder
ALT and GND modes may not be controlled by the pilot. To allow the transponder to be operated in ALT
mode while on the ground, for the purposes of performing periodic testing in accordance with the
requirements of 14 CFR Part 91.413, a special transponder ground maintenance test mode is provided.
To access ground maintenance mode in a G3X Touch system with GDU 4XX displays:
1. Access the Transponder page, press the Menu key.
2. Select Enable Maintenance Test to force the transponder into ALT mode.
To access ground maintenance mode in a G3X system with GDU 37X displays:
1. Access the Transponder Setup page via the Main Menu.
2. Change the setting for Ground Maintenance Test to Enabled to force the transponder into ALT
mode.
Transponder ground maintenance mode will be cancelled following a power cycle, or if the aircraft is
determined to be airborne.