Accident Sequence
On June 26, 2008, about 1630 Pacific daylight time, a Cessna 172N, registration N6360D, made a forced landing near El Cajon, California, after experiencing a loss of engine power. The aircraft was operated by California Flight Academy under 14 CFR Part 91 as an instructional flight. The certified flight instructor (CFI) and the student pilot were not injured, but the airplane sustained substantial damage. The flight had departed Gillespie Field Airport, El Cajon, about 1530 for a local instructional flight. Visual meteorological conditions prevailed, and no flight plan had been filed.
According to the CFI, while over San Vicente Reservoir, he simulated an engine failure by retarding the throttle. After approximately one minute of procedures, the CFI applied power but the engine did not respond. He then performed a forced landing to a field on a ranch. During the landing, the left wing tip struck the ground, resulting in structural damage to the left wing.
Examination and Testing
A Federal Aviation Administration (FAA) inspector examined the airplane at the accident site. The inspector observed fuel in both tanks and in the gascolator. The engine oil level was at 7 quarts, and the air filter was not obstructed. The wings were removed, and the airplane was recovered to the operator's hangar at Gillespie Field.
On July 10, 2008, an FAA inspector observed a test run of the engine. Fuel was supplied directly to the gascolator from a bucket via a line. The engine started and idled normally. Power was increased to 1800 rpm, and the carburetor heat was applied and found to operate normally. Power was further increased to 2000 rpm, and the engine was then shut down by moving the mixture control to the idle cutoff position.
Weather and Icing Conditions
The temperature and dew point at Gillespie Field at 1647 were recorded as 75 degrees Fahrenheit and 55 degrees Fahrenheit, respectively. Plotting these values on a carburetor icing probability chart indicated that the airplane was operating in the range for serious icing at glide power. According to the operator, the CFI did not apply carburetor heat prior to retarding the throttle during the simulated engine failure.