Accident Overview
On August 3, 2012, at approximately 0919 central daylight time, a Weatherly 620B, registration N2008S, was substantially damaged when it impacted terrain following a loss of engine power during takeoff. The accident occurred near Holcomb, Kansas. The pilot, the sole occupant, sustained minor injuries. The aircraft was operated by Farmers Aviation, Inc., under 14 Code of Federal Regulations Part 137 as an agricultural application flight. Visual meteorological conditions prevailed, and no flight plan was filed.
Pilot Report
The pilot reported completing a preflight inspection and pre-takeoff run-up with no anomalies. The takeoff roll was normal, and the aircraft lifted off within a reasonable distance. However, the pilot noted an approximately 30 rpm drop during takeoff compared to previous flights, though engine speed remained within normal operating range. After reaching about 50 feet of altitude, the engine began losing power. The pilot attempted to jettison the chemical load to maintain flight, but the aircraft impacted an open field approximately one mile north of the airstrip. The pilot stated that the engine had lost nearly all power by the time of impact. The pilot did not mention using carburetor heat during the run-up or the power loss event.
Aircraft and Engine Examination
Examination of the airframe and engine revealed no preimpact anomalies that could explain the loss of engine power. A subsequent re-examination also found no anomalies. The carburetor and magnetos were sent to the NTSB investigator-in-charge for further examination. The carburetor was disassembled with no anomalies noted. The right magneto was broken due to impact, but no anomalies were detected upon examination. The left magneto was intact and produced spark when rotated.
Weather Conditions
At 0854, weather conditions recorded at Garden City Regional Airport, about 15 miles east of the accident site, included a temperature of 22 degrees Celsius and a dew point of 19 degrees Celsius. According to the carburetor icing chart in FAA Special Airworthiness Information Bulletin CE-09-35, titled "Carburetor Icing Prevention," these temperature and dew point conditions fall within the range of susceptibility for icing during glide and cruise power settings, and within the range of susceptibility for serious icing during glide power.