Tube And Fabric Aircraft - Garmin GTX 330D Maintenance Manual

B.4 Tube and Fabric Aircraft
If it is necessary to replace the existing AN742 clamp, install a new AN742 clamp in accordance with AC
43.13-1B Chapter 11, Section 11, Clamping, and Section 15, Grounding and Bonding and the following
criteria.
Refer to table B-3 for hardware.
Install the conductive clamp on the tubular structure using the following procedure (refer to figure B-8).
1. Ensure all surface preparation material (e.g., primer, paint, etc.) is removed between the clamp and
the metallic tube over an area which is equal to the width of the clamp and 1 inch minimum length
for steel tubes; 2 inch minimum length for attachment to aluminum tubes, to ensure a good contact
surface.
2. Reinstall the existing bonding straps from the GTX mounting plate to the bonding clamp.
3. Verify the resistance between the GTX chassis and the aircraft ground structure does not exceed
2.5 mΩ.
4. After assembly and bonding check, prime the airframe tube and clamp in accordance with one of
the following.
• The approved aircraft maintenance manual
• MIL-PRF-85285 Type I, Color to suit (36081 Flat Gray Preferable) Coating: Polyurethane,
Aircraft And Support Equipment
• MIL-PRF-23377 Type I, Class N, Primer Coatings: Epoxy, High-Solids
190-00734-11
Rev. 6
GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Page B-9