Having spent 20 years in the Air Force as an aircraft mechanic and my last 5 working F-15s (a couple of years running a Periodic Phased Inspection Dock and then as a flight line Production Superintendent) at Tyndall AFB, Fl, I can maybe add some info on the recent crash. Tyndall had F-15 C/Ds that made in the late 70’s early 80’s. The F-15 has a “honeycomb” mesh filler system in its wings (mainly tips) and particularly its vertical stabilizers. These areas are x-rayed periodically for evidence of internal damage, external cracks, etc. In particular they are inspected for evidence of “water logging’ of the honeycomb mesh. When the filler material becomes waterlogged, the area expands and weakens and causes internal separation to various degrees. It is like comparing a dry sponge, which is hard and has load-carrying capabilities, to one that has been wetted a bit. The water gets in through seams and such and is hard to detect and also hard to stop. That’s why they paint these jets. It helps seal them. If evidence of water is found the usual method for repair is evacuation. Basically the water is slowly sucked out by vacuum action over several days and then the areas reexamined. It’s a fairly routine procedure. For more extensive damage and cracking there are more intensive repairs for damage to the honeycomb areas with a bondo-type material, and this repair is performed at a higher level of maintenance such as depot level by civilians. Or a contractor team on base will be dedicated to performing such repairs. When I was there, Tyndall had a dedicated contractor team, constantly performing these types of repairs.