- Location: Arco, Idaho
- Accident Number: WPR24FA201
- Date & Time: June 20, 2024, 12:55 Local
- Registration: N802TP (A1); N581TW (A2)
- Aircraft: AIR TRACTOR INC AT-802 (A1); AIR TRACTOR INC AT-502B (A2)
- Aircraft Damage: Destroyed (A1); Destroyed (A2)
- Defining Event: Midair collision
- Injuries: 1 Serious (A1); 1 Fatal (A2)
- Flight Conducted Under: Part 137: Agricultural (A1); Part 137: Agricultural (A2)
https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194510/pdf
https://data.ntsb.gov/Docket?ProjectID=194510
On June 20, 2024, at 1255 mountain daylight time, an Air Tractor AT-802 airplane, N802TP, and an Air Tractor AT-502B airplane, N581TW, were both destroyed when they were involved in a midair collision near Arco, Idaho. The pilot of the AT-802 was seriously injured and the pilot of the AT-502B was fatally injured. Both airplanes were operated as Title 14 Code of Federal Regulations Part 137 aerial application flights.
Two airplanes, an Air Tractor AT-502B and an Air Tractor AT-802, owned and dispatched by the same operator, were conducting aerial application operations from the same airport and in the same geographic area when they collided in flight during day visual meteorological conditions. Both airplanes had been dispatched from their base of operations to an airport near the operating area the morning of the accident, and each pilot was tasked to apply products to different agricultural fields.
After leaving the fields northwest of the airport, the AT-502B maneuvered south toward fields assigned to the AT-802. These fields were west of both the airport and the other fields assigned to the AT-502B. The AT-502B maneuvered to the south about the same time that the AT-802 departed the airport and flew west back toward its assigned fields. Both airplanes were flying at similar low altitudes above ground level.
Two witnesses traveling westbound on a highway observed one airplane, likely the AT-502B, traveling from north to south over the highway at low altitude. They also observed a second airplane, likely the AT-802, traveling toward the first on a northerly heading. They said the southbound airplane appeared to make a left turn in front of the northbound airplane. The northbound airplane then appeared to make a hard right turn before they collided. Impact damage and debris field findings were consistent with each airplane impacting the other’s right side.
According to operator personnel, the pilots discussed which fields each pilot would be responsible for, and they were aware of each other’s area of operations. Operator personnel also stated the company and pilots did not have formal deconfliction or communications plans, and that the pilots primarily used cell phone voice and text to communicate with each other and the ground crews. The last documented communication between the pilots occurred three hours before the accident.
The AT-802 pilot’s toxicological testing indicated that he had used or been administered ketamine, fentanyl, and ondansetron. These are common postaccident treatment medications, and there is a strong possibility that they were administered to the pilot after the accident. If so, the toxicology results would not constitute evidence of pre-crash ketamine, fentanyl, or ondansetron use. Other detected substances (dextromethorphan and naproxen) are not typically impairing with appropriate use. Whether they were used to treat active symptoms of minor acute illness could not be determined.
The AT-502B pilot had cardiovascular conditions, including coronary artery disease and diabetes, that were associated with increased risk of an impairing or incapacitating cardiovascular event, such as arrythmia, heart attack, or stroke. There is no autopsy evidence that such an event occurred, although such an event does not leave reliable autopsy evidence if it occurs just before death.
Based on HbA1c values, the AT-502B pilot’s diabetes was incompletely controlled at the time of his last FAA medical examination and remained incompletely controlled in the months before the accident. The fact that his medication-treated diabetes had been waived by the FAA indicates it is unlikely that significant medication side effects or long-term ocular or neurological complications of the disease had been identified as of that time. Symptoms such as fatigue or blurry vision may occur in incompletely controlled diabetes. Overall, the investigation could not determine whether the AT-502B pilot was experiencing impairing effects of his incompletely controlled diabetes, such as fatigue or blurry vision, at the time of the accident.
Both pilots were required to use corrective lenses to meet vision standards at all required distances. The AT-802 pilot was likely wearing corrective lenses at the time of the accident. Investigators could not determine if the AT502B pilot was wearing corrective lenses at the time of the accident.
The accident is consistent with both pilots failing to see and avoid each other in sufficient time to avoid a collision. However, the operation of both airplanes in the same geographic area increased the likelihood of a conflict between the two airplanes, the risks of which could have been reduced if the operator and pilots had developed and followed a formal deconfliction plan and the pilots had communicated their locations and intentions regularly during the flights. Both pilots likely had little or no situational awareness as to their proximity to the other airplane until immediately before impact.
- Probable Cause: A midair collision between two airplanes during aerial application operations due to both pilots’ insufficient awareness of their proximity to each other and their failure to see and avoid each other. Contributing to the accident was the operator and both pilots’ failure to develop and follow a deconfliction and communications plan.
- Pilot Information:
The airplanes’ operator reported that they did not have formal communication or deconfliction plans for airplanes operating in the same geographical area. The pilots communicated primarily through phone calls and text messages during operations. The AT-802 pilot’s cell phone was recovered, and a review of the text and phone logs on scene showed the last communication between the pilots was a 36-second phone call at 0958 on the day of the accident. No records or reports of radio communication between the two pilots were discovered during the investigation.
On June 21, 2024, the National Agricultural Aviation Association issued a Fly Safe message informing pilots of the importance of communication and planning when operating in the vicinity of other aircraft.
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