Accident Summary
The accident occurred during a forced landing. The airplane stalled and subsequently impacted trees and terrain.
Witness Observations
Witnesses reported that the engine was running rough and intermittently prior to the accident.
GPS Data
A global positioning system (GPS) receiver recovered at the accident site provided track data. During the last 10 seconds of recorded data, the airplane's ground speed ranged between 73.7 and 79.8 mph. The stall speed for the accident airplane with flaps retracted is 70 mph.
Fuel Contamination Findings
Post-accident fuel samples taken from the fuel strainer and both electric fuel pumps were contaminated with water and particulate. Both electric fuel pumps contained rust, water, and particulate. The carburetor float bowl and accelerator pump-well were contaminated with fine particulate resembling silicon sand. The same fine particulate was observed in the carburetor idle tube passage and nozzle well.
Fuel samples taken from the right main fuel cell and fuel selector were clear of debris and water. A fuel sample obtained from the departure airport was clear of debris and water.
Aircraft Usage History
The accident airplane had been operated approximately 164 hours in the last 35 years, 47 hours in the last 15 years, 35 hours in the last 5 years, and 35 hours in the last year.
Regulatory References
According to Federal Aviation Regulations (FAR), the pilot-in-command is required to complete an aircraft preflight inspection to determine if the aircraft is in an airworthy condition.
According to FAA Advisory Circular 20-43C, fuel having a cloudy appearance or definitely off-color should be suspected of contamination or deterioration and should not be used.
According to the Airplane Flying Handbook, significant and/or consistent water or sediment contamination are grounds for further investigation by qualified maintenance personnel. Each fuel tank sump should be drained during preflight and after refueling.