Incident Overview
During a solo instructional flight, a student pilot encountered a loss of engine power, necessitating a forced landing. The airplane subsequently struck trees and terrain.
Pilot's Account
The student pilot reported that approximately 30 minutes into the flight, he became disoriented and began a descent to read the name of a town on a water tower. As he descended, the engine started vibrating. He responded by applying carburetor heat and enriching the mixture, which restored normal engine operation for a few seconds. Noting his altitude at 2,200 feet, he turned off the carburetor heat. The engine then resumed vibrating, accompanied by a decrease in engine speed. He reapplied carburetor heat, but this time there was no significant change in engine behavior. With the airplane now at an altitude between 1,800 and 1,900 feet, it continued to vibrate and slowly lose engine speed. The pilot chose to land in a field rather than on a road, but during the landing, the airplane impacted trees. He stated that he had very little power available to clear the trees.
Engine Examination
Post-accident examination of the engine revealed evidence of exhaust gas emanating from a hole located above the last fin on the upper portion of the cylinder barrel. The hole penetrated into the 11 o'clock valve cover screw. The serviceable tag associated with the cylinder assembly was dated March 19, 2004, and identified the manufacturer as Superior.
Probable Cause
The official investigation did not state a probable cause for the accident.