DFW05FA111 · Cessna 172

A 10,000-hour Airline Transport Pilot (ATP) departed approximately 0715, to train a new company pilot in locating and reporting oil spills/leaks in oil fields. The company procedure was to conduct the flight below 500 feet (AGL), and once an oil leak was detected, orbit the site with 10 degrees of flaps while making his report. At 1307, another pilot performing pipeline patrol, spotted the wreckage and reported its location. Radar data obtained from Approach Control showed the accident airplane maneuvering "tracking back-n-forth", below 500 feet (agl), in the general area of the accident. The last radar hit, at 0843, had the airplane approximately two miles west of the accident site at an altitude of approximately 300 feet (agl). All components of the airplane were accounted for at the accident site. The initial impact mark was a ground scar, which exhibited fragments of red navigational lens, consistent with the left wingtip, was identified approximately eight feet south of the left wing. The main wreckage, with the engine still attached to the fuselage, was over a small crater. The impact marks were consistent with a left wing low and nose down attitude. The elevator trim tab was found 15 degrees tab-up, and the wing flaps were found extended to the 10 degree setting. Both wing tanks and or fuel lines had been breached by the impact. The right wing fuel tank had approximately 3.5 inches of fuel, and the left wing had approximately 2 inches of fuel in the tank. The main fuel tank selector valve was in the both position. A borescope inspection of the engine revealed no mechanical deformation on the valves, cylinder walls, or internal cylinder head. The left magneto produced spark at all posts at the magneto cap; the right magneto was destroyed by impact. Control continuity to all flight controls up to the rescue cuts, was established.

Verbatim NTSB analysis and probable cause from the NTSB dataset