Flying staple
Returning from an instruction flight on firing the cannon air-ground, and being part of a pair of F-104Gs, several staples came lose from the first one and impacted the second airplane that was following at a lower altitude.
The pilot of the second airplane saw them coming and hit. After the mission and returning to Base, an immediate post flight inspection they found signs of impact on the cockpit and the entrance of the engine.
They decided to take a look inside the engine and after opening it they found that the compressor had almost all of its blades damaged, specially the last echelons.
Once seeing these damages it was hard to comprehend how the airplane, with the engine in such condition, could reach the Base.