What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot states he did a gumps (gas, undercarriage, mixture, prop) check at least three times prior to landing; (roughly 5, 3 and 1 miles out) and swears that he saw, said and pointed to "three green / no red". Also stated it felt like a normal touchdown on mains then the nose gear ripped off the airplane. Stated he did not bounce, porpoise or make a hard landing.
Investigation of aircraft shows the nose landing gear (NLG) separated at the top of the inner strut and was 90 degrees when it separated. This is the position of the NLG during the extension cycle not down and locked. No damage to the mechanism that rotates the NLG nor horizontal scuffing on NLG tire. Corrosion was evident at the fracture surface of the top of the inner strut. Remaining metal at the fracture site and bolt threads show the bolts compressed the metal to different levels.
Runway ground markings shows first mark is a prop strike (15 strikes over 82'). After the first 3 props strikes, 7 gouges and paint marks start, that match up to fresh scrapes on the side of NLG fork which matches the last known position of the NLG based on aircraft inspection. This does not match the pilot statement. There is however also one fresh scrape on the front left side of the fork that when matched to a similar mark on the runway would indicate the nose wheel was in the forward position when in struck the ground.
Cockpit inspection found landing gear handle down, power on shows two main green lights on and NLG light out and red in transit light lit. Hydraulic pump can be heard. NLG squat switch is intact however striker plate has rotated out of position. When striker plate is moved back to where the wear marks show it being, the squat switch depressed and turned off the pump and red in transit light and lit the green NLG light. There is no evidence of a hydraulic leak from the landing gear extension and retraction system. The aircraft had 6-7 previous take offs and landings within the preceding few hours from the same pilot and no mechanical irregularities reported on the landing gear system.
Amended narrative...7/9/2021...
Further investigation after the engine was removed revealed the drag brace and link was articulated through the broken stops and up, into a "v" at the hinge point and sitting passed/higher than the strut housing. This is not a normal articulation direction. If all broken pieces are put close back to where they belong, and you start from retracted and move towards extended there is not enough room for these pieces to get into this position. This signifies the drag brace and link were in the extended position and a rearward force was applied (bounce, bump, porpoise) overloading the stops and allowing the NLG to collapse.
As the FAA filed it
PILOT STATES HE DID A GUMPS (GAS, UNDERCARRIAGE, MIXTURE, PROP) CHECK AT LEAST THREE TIMES PRIOR TO LANDING; (ROUGHLY 5, 3 AND 1 MILES OUT) AND SWEARS THAT HE SAW, SAID AND POINTED TO "THREE GREEN / NO RED". ALSO STATED IT FELT LIKE A NORMAL TOUCHDOWN ON MAINS THEN THE NOSE GEAR RIPPED OFF THE AIRPLANE. STATED HE DID NOT BOUNCE, PORPOISE OR MAKE A HARD LANDING.
INVESTIGATION OF AIRCRAFT SHOWS THE NOSE LANDING GEAR (NLG) SEPARATED AT THE TOP OF THE INNER STRUT AND WAS 90 DEGREES WHEN IT SEPARATED. THIS IS THE POSITION OF THE NLG DURING THE EXTENSION CYCLE NOT DOWN AND LOCKED. NO DAMAGE TO THE MECHANISM THAT ROTATES THE NLG NOR HORIZONTAL SCUFFING ON NLG TIRE. CORROSION WAS EVIDENT AT THE FRACTURE SURFACE OF THE TOP OF THE INNER STRUT. REMAINING METAL AT THE FRACTURE SITE AND BOLT THREADS SHOW THE BOLTS COMPRESSED THE METAL TO DIFFERENT LEVELS.
RUNWAY GROUND MARKINGS SHOWS FIRST MARK IS A PROP STRIKE (15 STRIKES OVER 82'). AFTER THE FIRST 3 PROPS STRIKES, 7 GOUGES AND PAINT MARKS START, THAT MATCH UP TO FRESH SCRAPES ON THE SIDE OF NLG FORK WHICH MATCHES THE LAST KNOWN POSITION OF THE NLG BASED ON AIRCRAFT INSPECTION. THIS DOES NOT MATCH THE PILOT STATEMENT. THERE IS HOWEVER ALSO ONE FRESH SCRAPE ON THE FRONT LEFT SIDE OF THE FORK THAT WHEN MATCHED TO A SIMILAR MARK ON THE RUNWAY WOULD INDICATE THE NOSE WHEEL WAS IN THE FORWARD POSITION WHEN IN STRUCK THE GROUND.
COCKPIT INSPECTION FOUND LANDING GEAR HANDLE DOWN, POWER ON SHOWS TWO MAIN GREEN LIGHTS ON AND NLG LIGHT OUT AND RED IN TRANSIT LIGHT LIT. HYDRAULIC PUMP CAN BE HEARD. NLG SQUAT SWITCH IS INTACT HOWEVER STRIKER PLATE HAS ROTATED OUT OF POSITION. WHEN STRIKER PLATE IS MOVED BACK TO WHERE THE WEAR MARKS SHOW IT BEING, THE SQUAT SWITCH DEPRESSED AND TURNED OFF THE PUMP AND RED IN TRANSIT LIGHT AND LIT THE GREEN NLG LIGHT. THERE IS NO EVIDENCE OF A HYDRAULIC LEAK FROM THE LANDING GEAR EXTENSION AND RETRACTION SYSTEM. THE AIRCRAFT HAD 6-7 PREVIOUS TAKE OFFS AND LANDINGS WITHIN THE PRECEDING FEW HOURS FROM THE SAME PILOT AND NO MECHANICAL IRREGULARITIES REPORTED ON THE LANDING GEAR SYSTEM.
AMENDED NARRATIVE...7/9/2021...
FURTHER INVESTIGATION AFTER THE ENGINE WAS REMOVED REVEALED THE DRAG BRACE AND LINK WAS ARTICULATED THROUGH THE BROKEN STOPS AND UP, INTO A "V" AT THE HINGE POINT AND SITTING PASSED/HIGHER THAN THE STRUT HOUSING. THIS IS NOT A NORMAL ARTICULATION DIRECTION. IF ALL BROKEN PIECES ARE PUT CLOSE BACK TO WHERE THEY BELONG, AND YOU START FROM RETRACTED AND MOVE TOWARDS EXTENDED THERE IS NOT ENOUGH ROOM FOR THESE PIECES TO GET INTO THIS POSITION. THIS SIGNIFIES THE DRAG BRACE AND LINK WERE IN THE EXTENDED POSITION AND A REARWARD FORCE WAS APPLIED (BOUNCE, BUMP, PORPOISE) OVERLOADING THE STOPS AND ALLOWING THE NLG TO COLLAPSE.