CEN09LA442

The student pilot stated that he conducted a preflight inspection and engine run-up and noted no anomalies. He departed and climbed to 2,000 feet when the engine started running rough and popping. The engine rpms dropped from 2,200 to 2,000 without the throttle being moved. The pilot leaned the fuel mixture until the engine reached peak temperature and then enriched the mixture to -30 degrees. The engine roughness and popping increased and the rpms began to drop. The pilot then made a forced landing to a pasture. The airplane collided with several fixed objects and sustained structural damage to the airframe. Examination of the airframe, flight controls, engine assembly and accessories revealed no anomalies. The Pilot's Operating Handbook specified that in case of engine problems the mixture control should be set to "rich".

On July 14, 2009, at 1745 central daylight time, a Cessna 172S, N2446F, registered to a private owner and operated by Sky Mays Flight Academy, experienced a total loss of engine power and made a forced landing to a pasture in the vicinity of Boyd, Texas. The instructional flight was conducted under the provisions of 14 Code of Federal Regulations Part 91 and no flight plan was filed. Visual meteorological conditions prevailed and the airplane sustained structural damage to the airframe. The student pilot reported minor injuries. The flight originated from Fort Worth Meacham International Airport (FTW), Fort Worth, Texas at 1732. The pilot stated he conducted a preflight inspection, started the engine, completed the required checklist items, taxied to the run up area and completed an engine run up, to include leaning the mixture and no anomalies were noted. He departed and climbed to 2,000 feet mean sea level when the engine started running rough and popping. The engine RPM dropped from 2,200 to 2,000 RPM without the throttle being moved. The pilot thought he had not leaned the engine to maximum power so he used the engine lean assist and "leaned it to peak temperature (getting an open box) on either cylinder 1 or 4 and enriched mixture to -30 degrees when the engine roughness and popping increased and the RPM started going down fast....I realized it was engine failure." Examination of the crash site by an inspector from the Federal Aviation Administration revealed the landing gear tracks began 800 feet east of the airplane final resting place. The aircraft traveled through 600 feet of pasture before colliding with a fence, becoming airborne, crossing over a gully, and a tree line, before the right horizontal stabilizer struck a tree and the airplane impacted a berm on the opposite side of a pond. Examination of the airframe, flight controls, engine assembly and accessories revealed no anomalies.