Amateur-built ZENITH CH 750 accident near Temple, Texas, September 10, 2018

The NTSB's narrative final · quoted from the NTSB record

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.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.