Accident Overview
On August 8, 2016, at about 1415 central daylight time, an Air Tractor AT-502B (registration N634LA) impacted a bean field near Hickory Ridge, Arkansas, following a collision with a transmission line during an aerial application flight. The aircraft was operated by Burnette Aviation, Inc. under 14 CFR Part 137. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight originated from a private airstrip at an undetermined time. According to information from an Arkansas Highway Patrol trooper, the airplane was spraying a field when it struck a transmission line during a turn. The line became entangled on the landing gear, and the airplane continued turning before hitting the terrain. The commercial pilot was fatally injured, and the airplane sustained substantial damage.
Pilot Information
The pilot held a commercial pilot certificate with ratings for single-engine land, multi-engine land, and instrument airplane. His logbook was not located, so total flight experience at the time could not be determined. A second-class medical certificate was issued on January 29, 2014, with the limitation "must wear corrective lenses and possess glasses for near and intermediate vision." According to the certificate, the pilot could not exercise airman privileges after January 31, 2016. On the medical application, he reported 19,550 total flight hours, with 300 hours in the preceding 6 months. He reported no medication use, medical conditions other than kidney stones in 1991, and no healthcare visits aside from a 2013 flight physical.
Aircraft Examination
The wreckage was examined on-site by FAA inspectors and a representative from Air Tractor. All major components were present. The transmission line was entangled around the empennage and tailwheel. Flight control continuity was established from the cockpit to the elevators and rudder. The aileron controls were damaged but showed no preimpact anomalies. Flap controls were continuous, and the flaps were set to 5°. The pilot's restraints were found unbuckled. No preimpact failures or malfunctions were observed in the airframe or engine.
Medical and Pathological Findings
An autopsy performed by the Arkansas State Crime Laboratory determined the cause of death as multiple blunt force injuries. First responders noted that the pilot did not appear to have been wearing a safety helmet or restraints. Toxicology testing conducted by the FAA's Bioaeronautical Sciences Research Laboratory was negative for carbon monoxide and ethanol. Acetaminophen, citalopram, and its metabolite N-desmethylcitalopram, and pioglitazone were detected in urine; citalopram, N-desmethylcitalopram, and pioglitazone were also found in heart blood. Acetaminophen is a non-impairing over-the-counter pain medication. Citalopram is a prescription antidepressant (Celexa), and pioglitazone is a diabetes medication (Actos). The presence of citalopram indicates treatment for depression, a disqualifying condition for medical certification, though the FAA may issue a special issuance after stability on approved medication. Pioglitazone use requires additional FAA evaluations to ensure diabetes control.
Review of medical records from the pilot's endocrinologist showed a type 2 diabetes diagnosis in 2006. In 2009, he underwent brain surgery to remove a pituitary tumor, resulting in loss of hormonal regulation, requiring replacement hormones. He developed peripheral neuropathy and kidney dysfunction from poorly controlled diabetes, including a foot burn due to lack of sensation and a right foot drop. He refused insulin therapy believing it would not be allowed by the FAA. At his most recent endocrinology visit in April 2016, his medications included citalopram, desmopressin, glimepiride, metformin, pioglitazone, Victoza, hydrocortisone, levothyroxine, and pregabalin (a potentially impairing medication for nerve pain). In March 2016, a family member contacted the FAA safety hotline reporting that the pilot was falling frequently, using "heavy duty psych meds," and exhibiting rage with threats to crash his airplane. An email report was made in April 2016 describing his medical conditions. The FAA requested information from the pilot in April 2016, and the matter was under evaluation at the time of the accident.