Accident Overview
On April 14, 2016, about 1530 eastern daylight time, a Cessna 175, registration N6792E, was substantially damaged during a forced landing on a highway in Wartburg, Tennessee. The student pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the instructional flight conducted under Title 14 Code of Federal Regulations Part 91. The flight originated at Rockwood Municipal Airport (RKW), Rockwood, Tennessee, about 1500, and was destined for Williamsburg-Whitley County Airport (BYL), Williamsburg, Kentucky.
Flight and Pilot Details
The purpose of the flight was for the student pilot to complete a solo cross-country flight. The student pilot stated he performed a preflight inspection and engine runup before departure. The takeoff and climb were normal; however, shortly after leveling off at 3,500 ft above mean sea level, the engine began to sputter. While checking the fuel mixture and fuel gauges, engine rpm dropped to about 1,000. After attempting a restart and being unable to regain engine power, the pilot performed a forced landing on a highway. During the landing, the airplane struck and then came to rest against a tree.
According to a first responder, there was fuel leaking from the airplane when emergency personnel arrived. Photos provided by a Federal Aviation Administration inspector revealed substantial damage: the right wing and engine were separated from the airplane; the outboard portion of the left wing was impact damaged; and the fuselage and empennage displayed impact damage.
Engine Examination
During an engine examination, it was noted that cylinders Nos. 2, 4, and 6 sustained impact damage. The crankcase was fractured between cylinders No. 5 and 6. The left and right magnetos produced spark at all leads when placed on a test stand. The spark plugs showed normal wear per the Champion aviation check-a-plug comparison chart. Fractured engine and metal components were found in the oil sump. Further examination revealed the No. 6 connecting rod cap was fractured. A metallurgical examination of the connecting rod cap revealed a fatigue fracture that originated at the oil transfer hole in the center of the rod cap.
Weather Conditions
The closest weather reporting facility was Oak Ridge, Tennessee (OQT), about 18 miles east of the accident site. At 1453, weather included wind from 110 degrees at 5 knots; visibility 10 statute miles; few clouds at 5,000 ft; temperature 22°C; dew point 8°C; and a barometric altimeter setting of 30.13 inHg.