What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) During climbout from Casper, WY the left engine started to run rough and the pilot returned to the airport for landing. Aircraft landed without further problems. The left engine was not shut down or propeller feathered during flight. Post flight investigation showed the left engine number 6 cylinder head had cracked on the exhaust side.
As the FAA filed it
(-23) DURING CLIMBOUT FROM CASPER, WY THE LEFT ENGINE STARTED TO RUN ROUGH AND THE PILOT RETURNED TO THE AIRPORT FOR LANDING. AIRCRAFT LANDED WITHOUT FURTHER PROBLEMS. THE LEFT ENGINE WAS NOT SHUT DOWN OR PROPELLER FEATHERED DURING FLIGHT. POST FLIGHT INVESTIGATION SHOWED THE LEFT ENGINE NUMBER 6 CYLINDER HEAD HAD CRACKED ON THE EXHAUST SIDE.