N120TFAir Tractor AT-502B · 2007

On May 31, 2015, about 0815 central daylight time, an Air Tractor 502B airplane, N120TF, struck power transmission line wires while maneuvering five nautical miles southwest of Archer City, TX. The commercial pilot, the sole occupant in the airplane, sustained serious injuries. The airplane sustained substantial damage to the fuselage, both wings, and the empennage. The airplane was registered to the Bank of Utah Trustee and operated by Chanay Aircraft Service Inc., Wichita Falls, TX , under the provisions of 14 Code of Federal Regulations Part 137 as an agricultural aerial application flight. Visual meteorological conditions prevailed for the flight, which was not operated on a visual flight rules flight plan. The flight originated from Wichita Valley Airport (F14) at 0645.

The accident site was located approximately 75 feet east of Texas State Highway 79. The terrain was flat grass pasture with short mesquite shrubs and some cactus.

Chanay Aircraft Services representatives reported that the pasture was being treated with a herbicide. The pilot had already made applications on other area pastures before moving to the pasture where the accident occurred.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge on June 29, 2015, the pilot stated that he didn't remember very much from the day of the accident.

The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.

The airplane sustained substantial damage to the fuselage, both wings, and empennage.

The single-seat, low-wing, fixed-gear airplane, was manufactured in 2007, and was powered by a Pratt and Whitney PT6A-34AG turbine engine rated at 750 horse power. The airplane was also equipped with a Hartzell three-bladed, adjustable pitch propeller.

The National Transportation Safety Board Pilot/Operator aircraft accident/incident report form received from the operator revealed that the airplane's most recent annual inspection was completed in December 2014. At the time of the accident the engine and airframe time was 4,100 hours.

A review of recorded data from a nearby automated weather observation station, elevation 998 feet, revealed that, at 1315, conditions were wind at 360 at 4 Knots, visibility of 10 statute miles, sky clear.

A set of cross-country transmission lines were running east-west, about 500 feet north of the accident site. These lines were damaged with the top two wires being broken and laying on the roadway. The three lower wires were intact but hanging low enough to cause a hazard to traffic on the highway (at about 6 feet above the roadway).

The wreckage was located on the east side of the highway in the pasture, approximately 500 feet southwest of the damaged transmission lines. The aircraft was laying upright, with the nose pointing south-southwest parallel to the highway. The aircraft sustained substantial damage to the fuselage forward of the cockpit. The wing leading edges exhibited crush damage of the leading edges and there were wing skin panels that were buckled with lines of popped rivets.

The tailwheel was suspended above the ground. All the flight control surfaces and all major aircraft components were locate in the immediate vicinity of the main wreckage. Both main landing gear legs, the propeller and engine reduction gearbox, and other miscellaneous aircraft parts were located between the initial impact marks and the main wreckage.

During an examination of the aircraft, continuity of all the flight controls was established.

The engine was damaged in the impact. The propeller and propeller reduction gearbox were separated from the engine. This separation occurred at the engine "A" flange. Two of the three propeller blades had their tips broken off near the beginning of the debris path. Blade A displayed torsional twisting and a 90 degree bend about 12 inches from the propeller hub. Blades B and C displayed torsional twisting and bending respectively.