The .025" skin is clearly insufficient to support the ELT antenna. I decided to fabricate a backing plate out of .062" aluminum that would span the area between the ribs and stiffen the skin at the mounting point. I cut the material to size and contoured it to the existing skin. I clecoed and match drilled the plate ont the bottom of the skin. I then countersunk the holes to match the holes in the skin and stiffeners. Finally, I drilled the hole for the antenna. We're ready from priming and final assembly.
