Aviation Accident Summaries

Aviation Accident Summary CEN15LA451

Carthage, IN, USA

Aircraft #1

N17292

CESSNA 150L

Analysis

The private pilot was conducting a personal local flight in the airplane. The pilot reported that the engine lost power during initial climb after takeoff. His attempts to restore power by adjusting the fuel mixture and throttle were unsuccessful. The pilot reported that he applied carburetor heat and that the engine began running more roughly but that he left the carburetor heat activated. He subsequently conducted and off-airport landing in a corn field, and the airplane nosed over. The engine was not examined because, after the accident, the owner removed the airplane from the accident site and sold the engine. However, a mechanic who was subsequently hired to overhaul the engine reported that it had been improperly assembled with noncertificated parts. Although the engine had been improperly assembled, there was no evidence that the improper assembly resulted in the reported loss of engine power; however, the extent of the improper assembly indicated that an engine failure was imminent. The weather conditions at the time of the accident were conducive to moderate carburetor icing at cruise power and serious icing at descent power. Federal Aviation Administration guidance indicates that the application of carburetor heat may result in engine roughness while the ice melts, which is consistent with the pilot's report. Based on the available information, the engine likely lost power due to carburetor icing.

Factual Information

On June 20, 2015, about 1100 central daylight time, a Cessna 150L, N17292, received substantial damage when it nosed over during a forced landing following a loss of engine power near Carthage, Indiana. The pilot was not injured. The airplane sustained damage to the firewall, vertical stabilizer, and right horizontal stabilizer. The aircraft was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not on a flight plan. The local flight was originating from Small Airfield (IN81), Carthage, Indiana, when the accident occurred.The pilot reported that after performing a pre-flight inspection and run-up of the airplane, he proceeded to takeoff. He reported that during the initial climb after takeoff the airplane's engine lost power. He stated that the engine speed was decreasing and he could not maintain altitude. He attempted to adjust the fuel mixture and throttle with no effect. He applied carburetor heat and the engine ran rougher, but he left it on anyway. The pilot subsequently made an off-airport landing to a corn field. During the landing roll, the nose landing gear dug into the soft mud and the airplane nosed over. The pilot/owner disassembled the airplane and removed it from the field prior to notification of the National Transportation Safety Board, or the Federal Aviation Administration (FAA). On January 15, 2016, FAA inspectors examined the airplane. The fuselage was present. The owner had removed the wings, doors, engine, radios, instruments, and sold them. An inspection of the fuselage revealed that the engine mount was torn, the nose gear was missing, the lower fire wall was wrinkled, the windshield was missing, the left horizontal stabilizer was twisted, and the top of the vertical stabilizer and rudder were damaged. The engine had been sold to an individual who then hired a mechanic to overhaul the engine. The mechanic stated that the engine was improperly assembled and had non certificated parts installed. He told an FAA inspector that the cylinder hold down nuts were not properly tightened, the crank case parting flange hardware was loose, the connecting rod cap bolts were not cotter pinned, the camshaft gear and crankshaft gear attaching hardware were not safety wired, the vacuum pump drive gear was not installed, the camshaft and lifters were not certificated parts, and the magnetos were worn out. As a result, the case halves were not repairable, the magnetos were not serviceable, the camshaft and lifters were not certificated, the crankshaft was damaged, and two of the cylinders were not serviceable. The mechanic's opinion was that the individual who reassembled this engine was not familiar with the manufacturer's maintenance/overhaul procedures or the associated regulatory guidance. Maintenance records were not available for the airplane. FAA Inspectors reported that the owner had destroyed the records prior to FAA involvement. At 1053, the reported weather conditions at the GEZ 15 miles southwest of the accident site included a temperature of 24 degrees Celsius and a dew point of 21 degrees Celsius. According to a carburetor icing probability chart, the reported temperature and dew point were in the range of susceptibility for moderate carburetor icing at cruise power and severe icing at descent power settings. According to FAA Special Airworthiness Information Bulletin CE-09-35, entitled "Carburetor Icing Prevention", a drop in engine speed in fixed pitch propeller airplanes was a warning sign of potential carburetor icing. The SAIB further stated that application of carburetor heat may result in engine roughness for short time while ice melts.

Probable Cause and Findings

The partial loss of engine power due to carburetor icing.

 

Source: NTSB Aviation Accident Database

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