Accident Sequence
During a touch-and-go maneuver, the pilot lifted off at 65 knots. The aircraft settled and would not climb out of ground effect. The pilot aborted the takeoff, and the plane continued off the end of the runway. To avoid obstructions, the pilot intentionally performed a ground loop. During the ground loop, the left main gear attachment U-bolt failed at an old crack.
Investigation Findings
An investigation revealed that a carburetor heat control clamp was loose, which allowed the carburetor heat to remain in the "off" position. The control cable had been re-rigged approximately 71 tach hours prior to the accident. Additionally, the air intake boot was improperly positioned, allowing unfiltered air to enter the carburetor.
Conditions
The temperature and dew point were 81 degrees Fahrenheit and 65 degrees Fahrenheit, respectively. According to icing probability charts, a serious carburetor icing hazard would have occurred at low power settings under those conditions.
Pilot Actions
The pilot reported that the carburetor heat operated during an engine run-up before takeoff and that he used carburetor heat during each landing. However, due to the loose clamp, the carburetor heat was not actually applied during the touch-and-go.