Installation Instructions

190-01007-A3 GTN 6XX/7XX AML STC Installation Manual
Rev. 4 Page 3-11
3.4.3 GMA 35 Rack Installation
Use the six 6-32 screws that accompany the GMA 35 installation kit to install the GMA 35 mounting rack
to a GTN 7XX mounting rack. The screws are installed from the bottom side of the GTN 7XX mounting
rack using through-holes to access the mounting locations on the GMA 35 mounting rack. Refer to
Figure A-2 and Figure A-8.
3.4.4 GMA 35 Unit Insertion and Removal
The GMA 35 is installed into the rack by sliding it straight in until it stops. A 3/32-inch hex drive tool is
then inserted into the hex hole at the bottom center of the unit. Rotate the hex tool clockwise while
pressing the unit on the front until the GMA 35 is firmly seated in the rack.
To remove the GMA 35 from the rack, insert the hex drive tool into the hex hole on the bottom center of
the unit and rotate counterclockwise until the unit is forced out about 3/8 inches and can be freely pulled
from the rack.
Be sure not to over-tighten the unit into the rack. The application of hex drive tool torque exceeding
15 in-lbs can damage the locking mechanism.
3.5 Weight and Balance
Weight and balance computation is required after the installation of the GTN is complete. Follow the
guidelines as established in AC 43.13-1B, Chapter 10, Section 2, as appropriate. Make appropriate entries
in the equipment list indicating items added, removed, or relocated along with the date the installation
was accomplished. Include your name and certificate number in the aircraft records. See Table 3-6 for a
sample calculation. Include a copy of the updated aircraft weight and balance in the aircraft POH/AFM.
Table 3-5 lists GTN 6XX/7XX and GMA 35 unit weights. Refer to Figure A-3 (GTN 6XX) and
Figure A-4 (GTN 7XX) for unit centers of gravity.
Table 3-5. LRU Weights
LRU Std. Wt [Metric Wt.]
GTN 750 (unit only) 7.4 lb [3.38 kg]
GTN 750 (with rack and backplate) 9.3 lb [4.24 kg]
GTN 725 (unit only) 6.1 lb [2.80 kg]
GTN 725 (with rack and backplate) 7.7 lb [3.52 kg]
GTN 650 (unit only) 5.5 lb [2.48 kg]
GTN 650 (with rack and backplate) 7.0 lb [3.20 kg]
GTN 635 (unit only) 4.8 lb [2.18 kg]
GTN 635 (with rack and backplate) 6.2 lb [2.82 kg]
GTN 625 (unit only) 4.2 lb [1.90 kg]
GTN 625 (with rack and backplate) 5.4 lb [2.48 kg]
GMA 35 (unit only) 1.4 lb [0.64 kg]
GMA 35 (with rack and backplate) 2.2 lb [1.00 kg]