What happened
Observers at the scene reported that the aircraft entered a steep nose-down attitude while still airborne. Shortly after this maneuver began, the aircraft crashed into a wooded area located near the airport. Witnesses noted that although the propeller appeared to be rotating, no engine noise was audible prior to the impact. The aircraft struck the ground in a nose-low, inverted position.
The investigation
A thorough examination of the wreckage revealed no evidence of pre-impact mechanical failures or malfunctions with the airframe or powerplant systems. Investigators focused heavily on environmental conditions and system settings to determine the cause of the sudden loss of control.
Weather data collected approximately 32 miles northwest at Augusta, Maine, indicated a temperature of 72 degrees Fahrenheit and a dew point of 46 degrees Fahrenheit. These conditions created a significant risk for serious carburetor icing. Despite this risk, investigators found that the carburetor heat control was set to the heat position both in the cockpit and at the carburetor air box.
Findings
Fuel quantity records were incomplete; the exact amount of fuel on board at the time of the accident could not be determined. However, maintenance logs showed the aircraft had been serviced with 5.5 gallons of fuel prior to the flight. Post-accident inspection revealed that the primer was found in an unlocked position and the magneto switch was in the off position.
The combination of weather conditions conducive to icing and the lack of audible engine operation despite a turning propeller suggests a loss of power due to carburetor ice accumulation, even with heat applied. The specific mechanical state of the ignition and primer systems remains unexplained but may have contributed to the inability to recover power.