HISTORY OF FLIGHT On June 5, 1993, about 1400 central daylight time, a Steen Skybolt, N94MS, registered to Mark S. Streitz, 3429 West Ridge Road, Joliet, Illinois, experienced a catastrophic engine failure while on a pleasure flight. An emergency landing in a soft wet corn field was made with substantial damage to the aircraft. Visual meteorological conditions prevailed at the time. No flight plan was filed. The private pilot had no injuries. The flight originated at Joliet Park District Airport, Joliet, Illinois, at 1345 hours. INJURIES TO PERSONS The private pilot reported no injuries. DAMAGE TO AIRCRAFT The aircraft was substantially damaged by crash impact forces. Upper and lower wings, tail section, nose cowl, fuselage, and gears show heavy damage. CREW INFORMATION The pilot holds a private license and has 377 total flight hours. AIRCRAFT INFORMATION The airplane is a Steen Skybolt, serial number MS1, manufactured in 1986. The aircraft was in storage until purchased by Mr. Mark S. Streitz in January 1993. The Lycoming engine HIO-360-B1A, serial number L-4834-51A was originally installed in a Hughes helicopter. The engine was purchased used, time in service unknown, and major overhauled January 29, 1982. One each used connecting rod was installed at this overhaul. The engine was assembled and test run on June 2, 1984. The aircraft and engine were removed from storage on May 27, 1991. It was noted in the engine log books that the engine was ground run every 3 or 4 months since the major overhaul. The aircraft was given an annual inspection on April 2, 1993, with a total time of 45.9 hours. The aircraft had 73.1 hours total time at the time of the accident. TEST AND RESEARCH Inspection of the Lycoming HIO-360-B1A engine revealed a broken connecting rod #2. Connecting rod bolt, part number 75061 fractured allowing the connecting rod to disengage from the crankshaft journal. It could not be determined if new connecting rod bolts were installed at the last engine overhaul.