What happened
The pilot reported conducting a preflight and engine runup prior to departure with no apparent issues. However, shortly after takeoff while climbing through 350 feet, the engine RPM dropped significantly and remained between 1,500 and 1,600. The pilot was unable to maintain altitude while attempting to return to the airport. The aircraft collided with trees and then struck the ground.
The investigation
Postcrash examination of the engine revealed that the carburetor discharge nozzle was plugged by contaminants. Additionally, the carburetor heat and mixture control cables were found disconnected. An engine run confirmed that the left magneto was improperly timed and all leads of the right magneto were shorted.
Findings
The passenger stated that the engine RPM was fluctuating during the ground check. According to witnesses, the engine did not appear to be developing full power at departure. The last annual inspection was performed on September 24, 1986.