Accident Overview
On April 22, 2014, at approximately 1310 central daylight time, N51990, an Air Tractor 502B, was destroyed following a collision with power lines and subsequent impact with terrain. The accident occurred while the aircraft was conducting aerial spraying operations over a hay field in Garfield, Kansas. The airline transport rated pilot sustained fatal injuries. The airplane was registered to Farmer's Spraying Service Incorporated, Pratt, Kansas, and operated by Gross Flying Service, Pratt, Kansas. Visual meteorological conditions prevailed, and no flight plan was filed for the flight conducted under 14 Code of Federal Regulations Part 137.
Witness Account
A witness who had hired the operator to spray his hay field for weevils reported hearing the airplane circle the field twice before observing it begin a south-to-north pass. He then saw a puff of smoke as the airplane struck a set of power lines approximately 60 feet tall that ran east-west along the southern edge of the field. The airplane descended behind a tree line, and the witness lost sight and sound of it. He drove toward the last seen location and discovered the wreckage on a dirt road east of the field, subsequently calling 911. No post-impact fire occurred.
Operator Statement
According to the operator, he typically handled spraying jobs himself but hired the pilot during busy periods. On the day of the accident, they had four loads to spray; the accident occurred on the fourth load. They had discussed taking a lunch break after the third load but decided to continue due to enthusiasm and increasing wind from the south-southeast at 17–18 mph. The operator noted that previous flights were normal and both aircraft performed well. The pilot appeared in good spirits and not fatigued. The operator loaded the pilot's aircraft with approximately 300 gallons of chemicals and refueled it from his own storage tank before both departed for separate fields; the operator learned of the crash only after landing.
The operator stated he had sprayed the field numerous times, but the pilot was unfamiliar with the area and its obstacles. He described the power lines as "H Poles" with two taut high-tension ground wires at the top, below which were darker, slack power lines that were easier to see. A stand of trees on the opposite side of the road made the top ground wires difficult to discern when approaching the field. The operator believed the pilot was setting up GPS lines along a haystack when he struck the power lines; the next pass would have been the first spray run.
Aircraft Examination
On June 10, 2014, the NTSB examined the aircraft and engine. The airframe sustained extensive impact damage to the fuselage, wings, and tail. Flight control continuity was confirmed to the cockpit. An after-market airbag system on both shoulder harnesses had deployed upon ground impact. No mechanical deficiencies were found with the aircraft or restraint systems. The turbine engine exhibited deep rotational scoring consistent with operation at impact, and no anomalies were noted that would have prevented normal operation. The three-bladed propeller had separated from the engine; blade damage was consistent with rotation at impact. No mechanical issues were identified with the propeller.
Site Description
An FAA inspector reported that the airplane struck the top two steel static cables, which were 3/8-inch wide and situated about 5 feet below the pole tops (approximately 55 feet above ground). The airplane crossed over trees before impacting terrain about 275 feet north of the power lines on a dirt road, then traveled an additional 145 feet to its final rest position. There was no evidence of tree strikes, but part of the aircraft impacted a large haystack adjacent to the road. The landing gear came to rest about 130 feet forward of the main wreckage. Wire strike marks were evident on the propeller blades and main landing gear. The pilot remained secured in a 5-point restraint system and was wearing a helmet with a glare shield.
Subsequent visits to the site showed that the utility company had reinstalled the two high-tension cables struck by the aircraft. It was observed that these top cables were more difficult to see than the lower, darker cables.