At about 1325 Eastern time, the airplane was substantially damaged during a forced landing to a field, following a loss of engine power in cruise flight. The airline transport pilot incurred minor injuries but the passenger was not injured. Visual conditions prevailed for the IFR cross-country flight. The airplane was in cruise flight when the engine began to run rough and the pilot noticed a decrease in oil pressure. The pilot was vectored to the nearest suitable airport but performed a gear-up forced landing to a field. Examination revealed a cylinder was cracked at the base. There was no oil on the dipstick, but significant amounts of oil on the engine cowling.
