Ayres S2R-G6 N61374 accident near Pine Bluff, Arkansas

Probable cause

A total loss of engine power due to fuel starvation as a result of an electrical short in the wiring to the manual fuel switch that closed the fuel valves.

NTSB analysis

The pilot was spraying a rice field with fertilizer when the "airplane began to lose altitude." The pilot attempted a forced landing in an open bean field. During the forced landing the airplane's right wing struck a tree, spinning the airplane around to the right. The airplane then impacted the terrain sideways, shearing off the landing gear, bending both wings, and buckling the fuselage. An examination of the engine showed evidence indicating the engine was not operating prior to impact. Additionally, the examination showed nothing that would have caused a loss of power or an in-flight engine shutdown. Further investigation determined that the airplane had previously experienced an uncommanded engine shut down. According to the wiring system schematic, the manufacturer did not install engine speed switches to automatically and electronically control the fuel system, but instead, installed pilot-activated switches for manual control of the fuel system. Examination of the system showed evidence of a short in the wires to the switch. The manufacturer stated that if a short in the wires occurred or if a switch failed due to contamination or corrosion, voltage could be sent to pin "B" on the Fuel Shutoff (Solenoid) Valve, causing the fuel shutoff valve to close.

Text from the NTSB. Open the NTSB docket for DEN08LA107 for the full record.