Removed existing ELT mount backing plate and made new plate that will rivet into adjacent top fuselage stringer to add stiffness. Match drilled all holes and riveted new mount backing plate to skin and stringer. This greatly improved stiffness and stability of ELT antenna. Next, placed gear leg fairings in position and marked mount hole locations. Drilled holes in flange of fairing and transfer drilled to fuselage bottom skin, insuring to miss all tubing. Enlarged holes to 17/64" to accept #10 Rivnuts.