N6113C

HISTORY OF FLIGHTOn August 8, 2019, about 0721 central daylight time, an Air Tractor AT-502B, N6113C, was destroyed when it was involved in an accident near Sumner, Iowa. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 positioning flight.

The flight originated from the Mt. Pleasant Municipal Airport, Mt. Pleasant, Iowa, about 0615 and was destined for Oelwein Municipal Airport (OLZ), Oelwein, Iowa. A witness at OLZ reported that the pilot overflew the runway but then continued north. The airplane appeared to be intact, and the engine seemed to be running normally at that time.

Based on multiple witness statements, the airplane continued about 14 miles north of OLZ before it turned south. Witnesses located about 2-1/2 miles north of the accident site reported observing the airplane overfly their homes at a low altitude. One witness noted that the airplane appeared to be in level flight, and the engine seemed to be operating normally.

A witness near the accident site observed the airplane approach from the west-northwest in a constant 20° left turn. The airplane struck the power lines; however, the airplane's flightpath was not affected. The airplane then nearly struck a building before it struck a second set of power lines. It then veered left, and the nose dropped. The airplane subsequently impacted a road, skidded across the road, and impacted the ground near a large tree. A postimpact fire ensued. The witness added that nothing seemed to be unusual about the airplane before the initial wire strike except that it was at a “very low altitude.” The airplane seemed to be intact, and the engine sounded normal. He also stated that the airplane remained in the shallow left turn as it struck the power lines and did not appear to be climbing or descending.

PERSONNEL INFORMATIONThe pilot's logbook was not available to the National Transportation Safety Board during the investigation. On his most recent medical certificate application, the pilot reported taking no medications and having diet-controlled diabetes. He was involved in a wire strike event in the accident airplane 8 days before the accident. Witnesses noted that after that wire strike, the pilot seemed shaken, and he was heard coughing and vomiting several days later.

AIRCRAFT INFORMATIONThe owner of an agriculture operation based at OLZ noticed damage to the propeller, windshield, and spray boom following the pilot’s previous wire strike. The airplane remained at OLZ until repairs were completed; the engine and propeller were removed, and the airplane was returned to service 3 days before the accident.

A maintenance entry dated August 5, 2019, indicated that the engine power section was removed for an unscheduled inspection due to a propeller strike. It was repaired, reinstalled, and approved for return to service.

METEOROLOGICAL INFORMATIONSunrise occurred at 0608. At the time of the accident, the sun was positioned about 12° above the horizon at an azimuth of 079° (relative to true north).

AIRPORT INFORMATIONThe owner of an agriculture operation based at OLZ noticed damage to the propeller, windshield, and spray boom following the pilot’s previous wire strike. The airplane remained at OLZ until repairs were completed; the engine and propeller were removed, and the airplane was returned to service 3 days before the accident.

A maintenance entry dated August 5, 2019, indicated that the engine power section was removed for an unscheduled inspection due to a propeller strike. It was repaired, reinstalled, and approved for return to service.

WRECKAGE AND IMPACT INFORMATIONDamage to two sets of power lines, a small roof-mounted antenna on a single-story building, and a power line support pole was consistent with the airplane striking them before impacting a two-lane road and coming to rest against a large tree. The accident site was in the yard of a mixed-use commercial/residential building. The main wreckage consisted of the fuselage, right wing, inboard portion of the left wing, and empennage. The outboard portion of the left wing and the left aileron had separated and were located near the power line support pole. The engine, with the propeller attached, had separated from the airframe and was located at the accident site. A postimpact fire consumed most of the fuselage.

A postaccident airframe examination did not reveal any evidence of an in-flight structural failure or flight control system anomaly. An engine examination revealed circumferential contact marks throughout the engine consistent with rotation at impact. No anomalies consistent with a preimpact failure or malfunction were observed.

MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy conducted by the Iowa Office of the State Medical Examiner, Ankeny, Iowa, attributed the pilot's death to multiple blunt force injuries with thermal injuries. The autopsy identified evidence of heart disease, a subarachnoid hemorrhage that appeared to be several days old, pulmonary hypertension, and chronic kidney disease. Medical records revealed the pilot received dialysis for kidney disease and was being treated for diabetes, which his primary care doctor described as "not well controlled." In addition, the pilot had a history of coronary artery disease treated with stent placement and high blood pressure treated with medication.

Toxicology testing was performed by the Federal Aviation Administration Forensic Sciences Laboratory. The testing detected hydrocodone and dihydrocodeine, fentanyl and norfentanyl, trazodone, and yohimbine in heart blood and liver tissue.

Hydrocodone and fentanyl were prescribed to the pilot for chronic pain due to spinal stenosis. Both are in a class of medications referred to as opioid analgesics and have the potential to be impairing. Dihydrocodeine and norfentanyl are metabolites of hydrocodone and fentanyl, respectively. Trazodone was prescribed for anxiety. It is in a class of medications referred to as serotonin modulators and may impair the mental and/or physical ability required for the performance of potentially hazardous tasks. Yohimbine is used as a dietary supplement for multiple reasons including impotence, diabetic neuropathy, high blood pressure, and chest pain. It has stimulant effects and may impair mental and physical ability to perform hazardous tasks.