Accident Overview
On October 16, 2014, at approximately 1129 eastern daylight time, a Rockwell International 112A, registration N1148J, operated by a private individual, struck a powerline pole and unmarked transmission lines before impacting the ground during a forced landing in Gainesville, Georgia. The aircraft was destroyed by a postcrash fire. The flight instructor and private pilot on board sustained fatal injuries. The flight, which originated about one minute earlier, was a local instructional flight from Lee Gilmer Memorial Airport (GVL) under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed.
Personnel and Flight
The left seat occupant, a 50-year-old commercial pilot, held flight instructor and instrument ratings. He reported 4,100 total hours and 500 hours in the previous six months. He had flown with the airplane owner on two prior occasions, logging flights on October 1 and 6, 2014. The right seat occupant, a 74-year-old private pilot, reported 711 total hours and 37 hours in the previous six months. He held a third-class medical certificate with a limitation to wear corrective lenses.
Aircraft Information
The Rockwell International 112A, serial number 428, was manufactured in 1975. It was powered by a 200-horsepower Lycoming IO-360-C1D6 engine and equipped with a Hartzell constant-speed propeller. The fuel system included integral 25-gallon tanks in each wing, with vent scoop assemblies on the lower wing skin.
Meteorological Conditions
A surface observation at Lee Gilmer Memorial Airport at 1153 reported wind from 280 degrees at 9 knots, visibility 10 statute miles, scattered clouds at 2,200 and 3,300 feet, overcast at 4,200 feet, temperature 14°C, dew point 9°C, and altimeter setting 29.92 inches of mercury.
Wreckage and Impact
The main wreckage was located at 34°16.201' N, 083°50.226' W, approximately 0.28 nautical miles from the departure end of runway 29. Two powerline poles were broken; one adjacent to the accident site showed damage consistent with aircraft contact. The descent path to the ground was calculated at about 59 degrees. A postcrash fire consumed the cockpit, cabin, and both wings. Examination revealed that the outer four feet of the left wing separated, and the fuel vent lines were detached at the vent scoop assembly. The forward-oriented vent tube was partially obstructed by tan material consistent with insect nest debris. The right wing fuel vent lines also showed blockages, including a round object 11/32 inch in diameter.
Engine and Fuel System Examination
The engine sustained heat damage but continuity of the crankshaft and valve train was confirmed. The servo fuel injector was heat-damaged; examination indicated the mixture was just off full rich and the throttle was wide open. The manifold valve had obstructions in multiple ports, estimated at 45% to 75% blockage. Analysis by the NTSB Materials Laboratory identified the obstructing material as a polyester, likely an organic polymer. The fuel selector valve was positioned to 'both' with no internal obstructions.