SEA00LA150

While descending through 2,000 feet, the Mooney M20E's Lycoming IO-360-A1A engine stopped operating. The pilot switched fuel tanks and activated the fuel boost pump without success, and then executed a forced landing to rough/uneven terrain in an agricultural field. On site examination revealed fuel in both fuel tanks. The FAA inspector assigned to the accident reported that in a post-crash examination and test run of the engine the 'fuel control servo appeared to be blocked for unknown reason' and that 'fuel pressure going in the fuel servo was considerably/extremely low at [the] outlet and would not sustain engine operation.' The fuel servo was removed and flow checked with no discrepancies noted. The servo was then re-installed in the aircraft and the FAA inspector observed a second test run during which the engine successfully operated with no discrepancies noted.

On August 1, 2000, approximately 1830 Pacific daylight time, a Mooney M20E, N1927Y, registered to Wrightco Motorcycle Accessories, Inc., and being flown by a private pilot, was substantially damaged during a forced landing six nautical miles southeast of Oregon City, Oregon. The pilot sustained minor injuries. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was personal, was operated under 14CFR91, and originated from Estacada, Oregon, and was en route to Mulino, Oregon.

The pilot reported in a telephonic interview that he had initiated a descent from 2,000 feet above sea level to his destination when the engine abruptly stopped operating. He then attempted to trouble shoot the power loss by selecting alternate fuel tanks, and then boost pump operation, without success. He then executed a forced landing to an agricultural field encountering rough terrain during the landing rollout.

Post-crash examination and test run of the engine by the Federal Aviation Administration's (FAA) Hillsboro, Oregon, Flight Standards District Office inspector assigned to the accident was conducted shortly after the accident. The aircraft was leveled at the site and both left and right fuel tanks were observed to be approximately half full. The inspector reported that during the test run, the "fuel control servo appeared to be blocked for unknown reason" and that "fuel pressure going in the fuel servo was considerably/extremely low at [the] outlet and would not sustain engine operation."

The fuel servo unit was removed from the aircraft's Lycoming IO-360-A1A engine and shipped to the Safety Board's Northwest Regional Office. It was subsequently flow checked at the facilities of Precision Airmotive on October 20, 2000. No discrepancies were noted during the flow check (refer to attached report).

The fuel servo was returned to the maintenance facility that had removed it with instructions to re-install it in the aircraft. The FAA's Hillsboro Flight Standards District Office inspector assigned to the investigation returned to the maintenance facility and observed a second test run of the engine. He reported that the engine successfully operated with no discrepancies noted.