What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) During a steep turn, the engine lost power. Flight instructor immediately took control of the aircraft and executed engine procedures. Carburetor heat was applied but did not help. The engine surged between 1500 and 1700 RPM and then dropped to 1300 RPM. The aircraft shook when set-up for best glide. Could not keep airspeed. Decision was made for off field landing. At 300 feet the engine quit. Landed the aircraft in a field. Determined that the cylinder cracked and the cylinder separated from barrel, causing a rough running engine.
As the FAA filed it
(-23) DURING A STEEP TURN, THE ENGINE LOST POWER. FLIGHT INSTRUCTOR IMMEDIATELY TOOK CONTROL OF THE AIRCRAFT AND EXECUTED ENGINE PROCEDURES. CARBURETOR HEAT WAS APPLIED BUT DID NOT HELP. THE ENGINE SURGED BETWEEN 1500 AND 1700 RPM AND THEN DROPPED TO 1300 RPM. THE AIRCRAFT SHOOK WHEN SET-UP FOR BEST GLIDE. COULD NOT KEEP AIRSPEED. DECISION WAS MADE FOR OFF FIELD LANDING. AT 300 FEET THE ENGINE QUIT. LANDED THE AIRCRAFT IN A FIELD. DETERMINED THAT THE CYLINDER CRACKED AND THE CYLINDER SEPARATED FROM BARREL, CAUSING A ROUGH RUNNING ENGINE.