CEN17LA241

The private pilot and two passengers were conducting a local sightseeing flight when the engine "sputtered ever so slightly" and then regained power. Three to 5 seconds later, engine power dropped to about 700 rpm. The pilot checked the engine controls in an attempt to regain engine power; when power was not restored, he initiated a forced landing to a field. During the forced landing, the airplane landed about 3/4 down the length of a field and impacted adjacent trees. During an initial examination, about 1 ounce of water was found in the gascolator. Continuity was established from the cockpit engine controls to the respective engine components. Fuel was found in the carburetor bowl and in the wing fuel tanks. A follow-up engine examination and functional test run did not produce any anomalies that would have prevented normal operation and production of rated horsepower. It is likely the water contamination found in the gascolator resulted in the partial loss of engine power.

On June 24, 2017, about 0930 central daylight time, a Cessna 172 airplane, N6474B, impacted trees during a forced landing following a loss of engine power near Fulton, Missouri. The private pilot and two passengers were not injured, and two passengers sustained minor injuries. The airplane sustained substantial damage to the wings and fuselage. The airplane was owned and operated by a private individual as a 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed at the time of the accident, and a flight plan was not filed. The local flight departed the Elton Hensley Memorial Airport, Fulton, Missouri, about 0915. According to the pilot, prior to the local sightseeing flight, he completed a preflight inspection of the airplane. He noted "little to no water" when he sumped the left wing fuel tank, and stated he sumped the right wing fuel tank. The left wing fuel tank contained about 9 gallons of fuel, and the right wing fuel tank contained about 7 to 8 gallons of fuel. While maneuvering during a local sightseeing flight, the engine "sputtered ever so slightly" and then regained power. About 3 to 5 seconds later, the engine dropped to about 700 RPM. The pilot checked the engine controls in an attempt to regain power. The pilot initiated a forced landing to a field. During the forced landing, the airplane landed about 3/4 down the available length of a field and impacted adjacent trees. During an initial examination at the accident site by a Federal Aviation Administration (FAA) inspector, the inspector found about 1 ounce of water in the gascolator. Continuity was established from the cockpit engine controls to the respective engine components. Fuel was found in the carburetor bowl and in the wing fuel tanks. On July 26, 2017, at the recovery facility, the engine was examined by FAA inspectors and a representative of Continental Motors. The engine was visually examined and no anomalies were noted. An external supply of aviation fuel was plumbed into the gascolator on the firewall of the airframe. Due to two broken rear engine mounts, a ratchet strap was used to secure the engine to the airframe engine mount. The engine started normally on the second attempt and allowed to warm up. The throttle was advanced to 1,000 RPMs and a magneto check was performed. Each magneto produced a drop of 50-75 engine RPMs. The engine was advanced to 2,300 RPM, and then back to 1,000 RPM for a second magneto check. The magneto check results were the same as the first magneto check. The throttle was reduced to idle, and the engine was shutdown using the mixture control. According to Continental Motors, the engine examination and functional test run did not produce any anomalies that would have prevented normal operation and production of horsepower. The airplane was configured to seat and restrain a total of 4 occupants.