On August 17, 2012, about 1345 mountain daylight time, the pilot of a Beech A36, N262EA, made a forced landing in a field near Ruleton, Kansas. The pilot and two passengers were not injured. The airplane was substantially damaged. The airplane was registered to KABAKY, LLC, Rapid City, South Dakota, and operated by 21st Century Equipment, Bridgeport, Nebraska, under the provisions of 14 Code of Federal Regulations Part 91 as a corporate/executive flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The local flight originated from Goodland, Kansas (KGLD), approximately 1330. According to the pilot's accident report, there was 9 quarts of oil in the engine crankcase (12 quarts maximum capacity) prior to his departure from Sidney, Nebraska. He arrived in KGLD about 1230. He did not indicate whether he checked the oil. After boarding two passengers, he departed KGLD at 1330, en route to Fort Morgan (KFMM), Colorado. Shortly after leveling off at a cruising altitude of 8,500 feet, the pilot heard engine RPM (revolutions per minute) increase and he noted that the tachometer was at the top of the gauge. The pilot was able to reduce power to 2,500 RPM, but was unable to restore thrust or maintain altitude. He extended the landing gear and made a forced landing in a wheat field near County Roads 74 and 9, about 12 miles northwest of KGLD. Post-accident examination revealed the right wing rear spar was broken. FAA inspectors went to the accident site and reported finding the turbocharger controller covered with oil. After the airplane was recovered to a hangar, they drained 5 quarts of oil from the crankcase. On September 27, 2012, the turbocharger controller was examined by the NTSB at Beegles Aircraft Service in Greeley, Colorado. Oil covered the controller piping. When shop air (35-95 psi) was introduced via the oil pressure inlet hose, the wastegate control valve opened and closed normally. A soapy solution was applied to all fittings. Air bubbles were noted at the elbow fitting of the outlet hose going to the wastegate controller. The outlet fitting was loosened and removed. The O-ring was discovered flattened. It was reseated and the elbow fitting re-torqued. Shop air and a soapy solution were reapplied. No more bubbles were observed. Examination of the airplane’s maintenance records revealed the last annual/100-hour inspection was performed on October 10, 2011. On that date, the engine, turbocharger, controller and wastegate were overhauled. The units were reinstalled on the airplane on November 12, 2011, at a Hobbs meter time of 1,907.6 hours. Routine oil changes followed on February 1, 2012 (1,909.8 hours0, April 26, 2012 (1.962.8 hours), and June 12, 2012 (38.5 hours, after the Hobbs meter was changed on April 26).