Accident Overview
A pilot reported that while conducting a third swath run over a field for agricultural spraying, the aircraft's engine began to run rough. In response, the pilot stopped spraying and attempted to gain altitude. However, the engine roughness increased, and shortly thereafter, the manifold pressure dropped. The pilot was unable to maintain flight and prepared to dump the chemicals. The aircraft subsequently crashed, impacting trees and terrain, resulting in the destruction of the aircraft.
Engine Examination
Following the accident, an examination of the engine was conducted. The inspection revealed carbon residue on the distributor of the left magneto and evidence of arcing between the #5 and #6 distributor terminals. No other abnormalities were reported.
Conclusion
No probable cause was stated in the investigation source.