Event
During the initial climb after takeoff, the pilot heard a loud bang followed by a partial loss of engine power. The pilot executed an emergency landing on a dry rice field. The airplane landed hard, causing the landing gear to shear off, and the aircraft tumbled before coming to rest on its belly.
Post-Accident Inspection
A post-accident inspection of the engine revealed that the number 7 cylinder was cracked along the cylinder fins and around both the top and bottom spark plug holes. Upon removal, a crack was found along the inside portion of the combustion chamber of the cylinder head, extending from one spark plug hole to the other, between the intake and exhaust valves.
Maintenance History
Review of the engine logbooks showed no entries indicating removal of the number 7 cylinder at any time between the last overhaul in 1999 and the accident date. The most recent inspection occurred five months prior to the accident.
Finding
The specific reasons for the cracks in the number 7 cylinder were not determined.