Accident Overview
On August 10, 2011, at about 1750 central daylight time, a Grumman G-164A airplane, registered as N127FC, sustained substantial damage in a forced landing after a loss of engine power during takeoff near Mansfield, South Dakota. The commercial agricultural application flight was conducted under 14 Code of Federal Regulations Part 137, with visual meteorological conditions prevailing and no flight plan filed. The aircraft was operated by the pilot, who was the sole occupant and reported no injuries.
Pilot Report
The pilot stated that the engine began losing power shortly after takeoff, leaving insufficient runway to return. The engine then lost power completely, and the pilot executed a forced landing to a bean field approximately one-quarter mile from the departure end of the runway. The impact resulted in substantial damage to the wings and fuselage.
Postaccident Examination
A postaccident inspection of the engine air intake system revealed debris in the carburetor heat section of the intake ducting, which had nearly blocked the duct entirely. Additional debris was found on the pressure side of the air filter, blocking about 25 percent of the duct cross-section. The agricultural operator noted that the debris appeared to consist of paper towels, possibly due to rodent activity. The debris was located in an area of the intake ducting that was not visible during a preflight inspection.
The engine was subsequently removed from the airframe and tested in a test cell without any component replacements. The test cell provided its own intake ductwork, so the airplane's intake assembly was not used. The engine started without difficulty and ran to 1,500 rpm. Due to a suspected bent crankshaft from the accident, the engine was not operated above 1,500 rpm for safety reasons.
Engine History
The engine had been overhauled in March 2011 and installed on the accident airplane in May 2011. At the time of the accident, the engine had accumulated approximately 240 hours since the overhaul.