Once the angle frame was out, the outer lower doubler in the aft belly beneath it showed corrosion as well, and was replaced.

Blue water runs downhill and collects at the lowest point it can reach, so the belly was where the trail ended. Each part had to come out before the next one could even be seen.

One leak, three layers of structure, and better than three months of work from the first finding to the last part going back in.