Jim Callahan FAA-DER has approved over 40,000 repairs during his career. Like
most aircraft repairs, many repairs were minor, yet significant enough to
require approval. For instance, even though a fastener or material
substitution is quick and easy it still needs to be approved. He was also a
Boeing author and instructor for the Structural Analysis for Engineering
Liaison course providing an engineering forum on detail structural analysis
techniques for repair purposes.