On January 15, 2003, at 0755 Pacific standard time, a Cessna A188A, N5638J, made a forced landing in an open field and came to rest in a ditch following a loss of engine power after takeoff from a private dirt strip near Brawley, California. Farm Aviation, Inc., owned and operated the airplane under the provisions of 14 CFR Part 137, as an agricultural application flight. The airplane sustained substantial damage. The commercial pilot was not injured. Visual meteorological conditions prevailed for the local area crop dusting flight, and no flight plan had been filed. The flight was scheduled to terminate at a private dirt strip. According to the pilot he conducted a preflight at 0730 that morning. He checked the fuel level, "which was full," and then sumped each wing looking for fuel contamination. He noted no discrepancies during the preflight. The crew then loaded 18 bags of TR10 (herbicide) on board the airplane. The pilot then started the engine to warm it up. After the oil temperature warmed up, he taxied to the end of runway 08. He conducted a run-up, which included checking both magnetos and cycling the propeller three times looking for a drop in rpm's, an increase in manifold pressure, and a decrease in oil pressure. He encountered no discrepancies during the run-up. About 1-2 minutes after takeoff, the pilot noted that the engine started to lose power (50 - 60-percent). The airplane also started to lose indicated airspeed and started to descend. He checked the magnetos to confirm that they were both in the ON position. He then advanced the propeller, throttle, and mixture to the full forward position, and activated the electric fuel boost pump. The pilot stated that the engine continued to lose power, and the airplane continued to descend. He reported that he began looking for an open field to make a forced landing. The pilot indicated that there was less than 1/4 mile in which to make the forced landing. After landing, the airplane bounced and rolled into a ditch after he applied full flaps and brakes. A Federal Aviation Administration (FAA) inspector performed a visual inspection of the engine. He manually rotated the propeller, and established mechanical and valve train continuity. He obtained thumb compression in firing order. The engine was crated up under the supervision of the FAA, and shipped to the Teledyne Continental Motors (TCM) facility in Mobile, Alabama, on February 21, 2003. AIRCRAFT INFORMATION The airplane had a Teledyne Continental Motors IO-520-D55 engine, serial number 821984-R installed. TCM overhauled the engine. The engine had been reinstalled on the accident airplane on August 13, 2002. Total time on the engine was 17.5 hours. The propeller governor had been overhauled by Santa Monica Propellers, Santa Monica, California, and returned to service on August 30, 2002. The propeller assembly was reinstalled on the accident airplane on September 5, 2002. TESTS AND RESEARCH TCM received the engine on March 13, 2003. TCM completed a teardown inspection on August 12, 2003, under the auspices of the Safety Board investigator-in-charge (IIC), and a representative from TCM who was a party to the investigation. TCM noted no discrepancies during the external inspection of the engine. They bench tested both magnetos and they operated normally through all rpm ranges. TCM removed the spark plugs. According to the Aviation Check-A-Plug AV-27 Chart, the spark plugs exhibited normal operating signatures. The internal inspection of the engine revealed no mechanical anomalies. TCM bench tested the fuel pump, throttle body/metering unit, and manifold valve. All three components met the manufacturer's specified parameters with no discrepancies noted. All six of the fuel injector nozzles were unobstructed and undamaged. The lubrication system was undamaged. The propeller governor, model number C290D3-K/T9, serial number 772897, was shipped to the manufacturer, McCauley Propeller Systems, Vandalia, Ohio, on August 29, 2003. An FAA inspector from the Cincinnati, Ohio, Flight Standards District Office oversaw the inspection of the propeller governor at McCauley on September 9, 2003. The drive gear rotated manually by hand with no obstructions encountered. The propeller governor bench tested to manufacturer specifications, with the exception of the MAX rpm test. Manufacturer specifications for MAX rpm were 2,850 +/- 10 rpm. The accident propeller governor's MAX rpm was 2,794 rpm. McCauley stated that the lower than specified MAX rpm setting could be as a result of an on-aircraft adjustment. They noted no further discrepancies during the bench tests.