What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot released tie down chains and removed wheel chocks. Started engine for the purpose of taxiing to the wash rack. Pilot exited aircraft, with engine running at approximately 900 RPM, to retrieve his cell phone from his truck. Aircraft started to move under its own power. Pilot tried to stop aircraft by holding onto tail, but was unsuccessful. Aircraft continued in a left 180 turn and struck another aircraft in the tie down area. Subject aircraft's propeller struck second aircraft, damaging the right wing. Reference block 11. This is an estimate. Block 31, items h. and I. Both times are zero.
As the FAA filed it
PILOT RELEASED TIE DOWN CHAINS AND REMOVED WHEEL CHOCKS. STARTED ENGINE FOR THE PURPOSE OF TAXIING TO THE WASH RACK. PILOT EXITED AIRCRAFT, WITH ENGINE RUNNING AT APPROXIMATELY 900 RPM, TO RETRIEVE HIS CELL PHONE FROM HIS TRUCK. AIRCRAFT STARTED TO MOVE UNDER ITS OWN POWER. PILOT TRIED TO STOP AIRCRAFT BY HOLDING ONTO TAIL, BUT WAS UNSUCCESSFUL. AIRCRAFT CONTINUED IN A LEFT 180 TURN AND STRUCK ANOTHER AIRCRAFT IN THE TIE DOWN AREA. SUBJECT AIRCRAFT'S PROPELLER STRUCK SECOND AIRCRAFT, DAMAGING THE RIGHT WING.REFERENCE BLOCK 11. THIS IS AN ESTIMATE. BLOCK 31, ITEMS H. AND I. BOTH TIMES ARE ZERO.