Incident Overview
A certified flight instructor (CFI) was monitoring a private pilot during practice of unusual attitude recovery maneuvers. During the setup for a maneuver, a power reduction was made from climb power to nearly idle. When the throttle was subsequently advanced to full power, the engine lost power and did not respond. Several attempts to restart the engine were unsuccessful.
Emergency Response
The CFI monitored the descent as the private pilot attempted to set up for a forced landing to a road. When the intended landing point was overshot, the CFI took control of the airplane, maneuvered between several trees, and set the aircraft down hard in a pasture.
Investigation Findings
Disassembly of the carburetor revealed that the float attachment bracket was detached and separated from the carburetor bowl assembly. Aircraft records indicated that a carburetor float kit had been installed on May 7, 1996. Tap screws were used to attach the float attachment brackets to the carburetor bowl, which stripped the holes for the attachment brackets. The manufacturer's installation instructions specified that set screws should have been used on the attachment brackets. Additionally, what appeared to be glue residue was found on the threads of the tap screws.