CEN18LA385

Before takeoff, the private pilot completed a preflight inspection, engine start, and two engine run-ups with no anomalies noted. Shortly after takeoff, when the airplane was about 400 ft above ground level, the engine began to vibrate, and the pilot noticed a partial loss of power. He suspected carburetor icing and applied carburetor heat but observed no change to the engine power. Due to the low altitude, the pilot chose to execute a forced landing to a field. The airplane touched down in the soft field, and the nose gear collapsed. Postaccident examination of the airplane, which included the fuel system, revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. The pilot reported that he should have applied carburetor heat before takeoff to clear any potential ice buildup during the taxi and subsequent engine run-ups. The airplane was operating in an area with weather conditions conducive to the formation of serious carburetor ice at glide power settings. Thus, the partial loss of engine power was likely due to an accumulation of carburetor ice while operating at reduced engine power settings before takeoff.

On September 10, 2018, about 0845 central daylight time, a Lynch Zenith 750 experimental amateur-built airplane, N946JY, impacted soft terrain during a forced landing following a partial loss of engine power during initial climb near Temple, Texas. The private pilot sustained minor injuries, and the airplane sustained substantial damage to the fuselage. The airplane was registered to and operated by a private individual under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The local flight departed the Draughon-Miller Central Texas Regional Airport, Temple, Texas. According to the pilot, he had recently completed the building of the airplane and was operating under the phase 1 flight test experimental operating limitations. Prior to takeoff, he completed a preflight, engine start, and two engine run-ups. No abnormal engine indications or anomalies were noted during those tasks. Shortly after takeoff about 400 ft above ground level, the engine began to vibrate, and a partial loss of power was noticed by the pilot. The pilot suspected carburetor icing and applied carburetor heat. No change to the engine power was observed. Due to the low altitude, the pilot elected not to make a turn back to the runway and to execute a forced landing to a field that was in front of him. The airplane touched down in a soft field, and the nose gear collapsed. The airplane skidded about 20 yards and came to rest upright. The pilot departed with about 24 gallons of fuel in the fuel tanks. After the accident, no fuel was found to be leaking from the airplane. The pilot reported that he should have applied carburetor heat prior to takeoff to clear any potential icing buildup during taxi from ramp and subsequent engine run-ups. The pilot stated the Federal Aviation Administration (FAA) inspector examined the airplane and did not find any anomalies that would have precluded normal operation. The carburetor icing probability chart included in Federal Aviation Administration Special Airworthiness Information Bulletin No. CE-09-35, Carburetor Icing Prevention, indicated that the airplane was operating in an area that was associated with a serious risk of carburetor ice accumulation at glide power settings (Figure 1). Figure 1 - FAA Carburetor Icing Probability Chart