You are only required to report the following under NTSB 830 for aircraft under 12,500lbs:
1) Flight control system malfunction or failure; (2) Inability of any required flight crewmember to perform normal flight duties as a result of injury or illness; (3) Failure of structural components of a turbine engine excluding compressor and turbine blades and vanes; (4) In-flight fire; or (5) Aircraft collide in flight; (6) Damage to property, other than the aircraft, estimated to exceed $25,000 for repair (including materials and labor) or fair market value in the event of total loss, whichever is less.
Not quite...You are also required to report any "accident" in addition to the above and the definition of an accident is:
Aircraft accident means an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage.
Substantial damage means damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft, and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling, dented skin, small punctured holes in the skin or fabric, ground damage to rotor or propeller blades, and damage to landing gear, wheels, tires, flaps, engine accessories, brakes, or wingtips are not considered “substantial damage” for the purpose of this part.
I guess in their wisdom that the FAA decided that
A large, jagged hole was left with most of the windscreen gone, and the interior trim, headliner, and plastics pulled apart and dangling. The glareshield and top of the instrument panel were outside the cockpit, in front of us.
...was not "substantial damage"...though of course we weren't there and it may have not been as bad as I imagine from this description....