What happened
During a flight training session involving unusual attitude recovery maneuvers, the engine of the aircraft lost power and failed to respond when the throttle was advanced from nearly idle to full power. The failure occurred during the setup for a maneuver following a reduction from climb power.
Following the loss of power, several attempts to restart the engine were unsuccessful. As the aircraft descended, the private pilot attempted to coordinate a forced landing toward a road. However, after overshooting the intended landing point, the flight instructor took control of the airplane. The instructor maneuvered the aircraft between several trees and performed a hard landing in a pasture.
There were no injuries resulting from the accident.
The investigation
Upon disassembly of the carburetor, investigators discovered that the float attachment bracket had detached and separated from the carburetor bowl assembly. A review of aircraft records indicated that a carburetor float kit had been installed on May 7, 1996.
Investigation of the installation revealed that tap screws were used to attach the float attachment brackets to the carburetor bowl, which resulted in the stripping of the attachment holes. The manufacturer's installation instructions specified that set screws should have been utilized for the attachment brackets instead. Additionally, residue appearing to be glue was found on the threads of the tap screws.