What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Aircraft was enroute to mount vernon, IL. While flying over Missouri the pilot noticed the oil pressure fluctuating, and decided to land at Salem, MO (K33) to check the oil level. The aircraft landed a little hard and the bracket holding the locking pins twisted, and the pin came loose. This caused the manual gear mechanism to let loose and the gear retracted back up to the wing. The aircraft then slid down the runway about 150 feet and came to rest on the side of the runway.
As the FAA filed it
AIRCRAFT WAS ENROUTE TO MOUNT VERNON, IL. WHILE FLYING OVER MISSOURI THE PILOT NOTICED THE OIL PRESSURE FLUCTUATING, AND DECIDED TO LAND AT SALEM, MO (K33) TO CHECK THE OIL LEVEL. THE AIRCRAFT LANDED A LITTLE HARD AND THE BRACKET HOLDING THE LOCKING PINS TWISTED, AND THE PIN CAME LOOSE. THIS CAUSED THE MANUAL GEAR MECHANISM TO LET LOOSE AND THE GEAR RETRACTED BACK UP TO THE WING. THE AIRCRAFT THEN SLID DOWN THE RUNWAY ABOUT 150 FEET AND CAME TO REST ON THE SIDE OF THE RUNWAY.