What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Note 1: the pilot has had 0 hours in make/model, in the last 90 days and in the last year. The system does not allow this to be entered, so I am noting it correctly here.
Note 2: times, headings, measurements & altitudes are approximate. The weather conditions were clear skies, a light variable breeze, & warm, reported by other people at the scene. The runway is a grass runway with warnings about gopher holes on the runways. The pilot was wearing his seat belt; but no shoulder harnesses were installed in this aircraft. The aircraft was taxiing on the runway in Opheim, MT. The pilot stated he did not intend on flying, but was only taxiing for familiarity. The pilot had taxied to one end of the runway and was taxiing back when the aircraft rotated forward on the nose strut, ending up inverted. The top of the rudder was bent with some damage transmitted to the upper hinge point area. The left lift struts were bent about midpoint, there was slight damage on the left wing tip, one prop blade was bent back, the nose gear was bent slightly back and to the right, with the nose gear wheel assembly rotated to almost 90 degrees, well beyond the normal travel stops, and the top cowling is displaced at both the forward and aft edges. Fuel was coming out of the fuel tanks while it was upside down. The grass and dirt disturbed by the nose tire for the nose gear was wider than the nose wheel tire rolling in direction of travel, with two spots at the end of the disturbed dirt and grass that are deeper and seem to match a prop blade. The only injury the pilot had was cuts on his head, he did not go to a hospital, but went home and treated them himself. The pilot was not current for flying, and did not have a current medical. The bolt that secures the steering horn to the top of the strut had broken on the head side, and the nut end of the bolt (nut still attached) had backed out allowing the steering horn to disengage from the top of the strut.
As the FAA filed it
NOTE 1: THE PILOT HAS HAD 0 HOURS IN MAKE/MODEL, IN THE LAST 90 DAYS AND IN THE LAST YEAR. THE SYSTEM DOES NOT ALLOW THIS TO BE ENTERED, SO I AM NOTING IT CORRECTLY HERE.
NOTE 2: TIMES, HEADINGS, MEASUREMENTS & ALTITUDES ARE APPROXIMATE. THE WEATHER CONDITIONS WERE CLEAR SKIES, A LIGHT VARIABLE BREEZE, & WARM, REPORTED BY OTHER PEOPLE AT THE SCENE. THE RUNWAY IS A GRASS RUNWAY WITH WARNINGS ABOUT GOPHER HOLES ON THE RUNWAYS. THE PILOT WAS WEARING HIS SEAT BELT; BUT NO SHOULDER HARNESSES WERE INSTALLED IN THIS AIRCRAFT. THE AIRCRAFT WAS TAXIING ON THE RUNWAY IN OPHEIM, MT. THE PILOT STATED HE DID NOT INTEND ON FLYING, BUT WAS ONLY TAXIING FOR FAMILIARITY. THE PILOT HAD TAXIED TO ONE END OF THE RUNWAY AND WAS TAXIING BACK WHEN THE AIRCRAFT ROTATED FORWARD ON THE NOSE STRUT, ENDING UP INVERTED. THE TOP OF THE RUDDER WAS BENT WITH SOME DAMAGE TRANSMITTED TO THE UPPER HINGE POINT AREA. THE LEFT LIFT STRUTS WERE BENT ABOUT MIDPOINT, THERE WAS SLIGHT DAMAGE ON THE LEFT WING TIP, ONE PROP BLADE WAS BENT BACK, THE NOSE GEAR WAS BENT SLIGHTLY BACK AND TO THE RIGHT, WITH THE NOSE GEAR WHEEL ASSEMBLY ROTATED TO ALMOST 90 DEGREES, WELL BEYOND THE NORMAL TRAVEL STOPS, AND THE TOP COWLING IS DISPLACED AT BOTH THE FORWARD AND AFT EDGES. FUEL WAS COMING OUT OF THE FUEL TANKS WHILE IT WAS UPSIDE DOWN. THE GRASS AND DIRT DISTURBED BY THE NOSE TIRE FOR THE NOSE GEAR WAS WIDER THAN THE NOSE WHEEL TIRE ROLLING IN DIRECTION OF TRAVEL, WITH TWO SPOTS AT THE END OF THE DISTURBED DIRT AND GRASS THAT ARE DEEPER AND SEEM TO MATCH A PROP BLADE. THE ONLY INJURY THE PILOT HAD WAS CUTS ON HIS HEAD, HE DID NOT GO TO A HOSPITAL, BUT WENT HOME AND TREATED THEM HIMSELF. THE PILOT WAS NOT CURRENT FOR FLYING, AND DID NOT HAVE A CURRENT MEDICAL. THE BOLT THAT SECURES THE STEERING HORN TO THE TOP OF THE STRUT HAD BROKEN ON THE HEAD SIDE, AND THE NUT END OF THE BOLT (NUT STILL ATTACHED) HAD BACKED OUT ALLOWING THE STEERING HORN TO DISENGAGE FROM THE TOP OF THE STRUT.