What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The pilot stated that there was a green light indicating that the landing gear was down and locked and that they confirmed that visually, but during landing roll-out the right landing gear collapsed. Because of the configuration of the landing gear on this aircraft, it is not understood how one of the main landing gear could collapse with weight on wheels. An eye-witness stated that he observed the event and that the right main landing gear was not fully extended. A gear swing was conducted and the landing gear system operated normally.
As the FAA filed it
THE PILOT STATED THAT THERE WAS A GREEN LIGHT INDICATING THAT THE LANDING GEAR WAS DOWN AND LOCKED AND THAT THEY CONFIRMED THAT VISUALLY, BUT DURING LANDING ROLL-OUT THE RIGHT LANDING GEAR COLLAPSED. BECAUSE OF THE CONFIGURATION OF THE LANDING GEAR ON THIS AIRCRAFT, IT IS NOT UNDERSTOOD HOW ONE OF THE MAIN LANDING GEAR COULD COLLAPSE WITH WEIGHT ON WHEELS. AN EYE-WITNESS STATED THAT HE OBSERVED THE EVENT AND THAT THE RIGHT MAIN LANDING GEAR WAS NOT FULLY EXTENDED. A GEAR SWING WAS CONDUCTED AND THE LANDING GEAR SYSTEM OPERATED NORMALLY.