History of Flight
On May 23, 2012, at 1049 central daylight time, an Air Tractor Inc. AT-802A (N4126T) and a Grumman G-164C (N996QC) collided in flight while maneuvering east of Sedgwick, Arkansas. Both aircraft were conducting aerial application flights under 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed. The Air Tractor had departed a private strip near Bono, Arkansas, at 1048 and was operating locally. The Grumman departed a private strip near Light, Arkansas, just prior to the collision and was also operating locally.
The Grumman pilot reported that he approached the field from the northeast intending to start a spray run on the south side of the field, traveling southwest. He observed several other airplanes but did not see the Air Tractor. He stated that upon completing 50% of his first spray pass, his airplane and the Air Tractor collided. The field he was spraying and the field the Air Tractor was flying over were separated by two field roads and a drainage ditch approximately 100 feet wide.
The Air Tractor departed with the intention of applying herbicide to a rice crop south of and bordering the field being sprayed by the Grumman.
GPS data recovered from the Air Tractor depicted its flight from departure at 1048:07 until the accident. The flight track proceeded east for about 30 seconds, then turned north. Just prior to the accident, the Air Tractor was flying north. The GPS altitude started at 55 feet, increased to 135 feet, then decreased. The last recorded altitude was 110 feet. The altitude over the target rice field started at 121 feet and descended to 113 feet.
After the collision, the Air Tractor continued several hundred feet north, impacted terrain, and came to rest inverted. The Grumman continued several hundred feet west, impacted terrain, and came to rest on its left side. There were no ground witnesses, and no radar data was available. Neither pilot was receiving radar flight following services nor in voice communications with each other; such services were not required.
Personnel Information
The Air Tractor pilot, age 51, held a commercial pilot certificate with ratings for airplane single- and multiengine land, instrument airplane, and rotorcraft-helicopter. He was issued a second-class medical certificate on April 3, 2012, with the limitations “Not valid for any class after April 30, 2013” and “must have available glasses for near vision.” On his most recent insurance application dated October 20, 2011, he reported 15,674.5 total hours, including 14,128.3 in agricultural operations, 790 hours in the AT-802, and 490 hours in the previous 12 months. He completed a flight review in September 2011. The accident report form from Miles Flying Service reported 15,800 total hours, with 916 in the accident airplane make and model. His most recent medical application estimated 16,500 total hours, with 75 in the previous 6 months.
The Grumman pilot, age 55, held a commercial pilot certificate with ratings for airplane single- and multiengine land, instrument airplane, and rotorcraft-helicopter. He was issued a second-class medical certificate on February 29, 2012, with the limitation “Must wear corrective lenses. Not valid for any class after 2/28/2013.” He reported 17,320 total flight hours, including 11,668 in the accident airplane make and model. He completed a flight review on December 2, 2011.
Aircraft Information
The Air Tractor AT-802A (serial number 802A-0261) was predominantly yellow with blue striping, manufactured in 2007. It held an FAA special airworthiness certificate for restricted operations. It was powered by a Pratt and Whitney PT6A-65AG engine rated at 1,295 horsepower, equipped with a 5-blade Hartzell propeller. The airplane was registered to and operated by Miles Flying Service, Inc., and was maintained under an annual inspection program. An annual inspection was completed on April 24, 2012, at an airframe total time of 3,381 hours.
The Grumman G-164C (serial number 19C) was predominantly yellow, manufactured in 1978. It held an FAA special airworthiness certificate for restricted operations. It was powered by a Garrett TPE331-10 engine rated at 940 horsepower, equipped with a 4-blade Hartzell propeller. The airplane was registered to HDS Inc., operated by Kin-CO Ag Aviation, Inc., and was maintained under an annual inspection program. An annual inspection was completed on March 20, 2012, at an airframe total time of 4,103.3 hours.
Meteorological Information
The closest official weather observation station was Walnut Ridge Regional Airport (KARG), Walnut Ridge, Arkansas, located 10 nautical miles northwest of the accident site. The routine aviation weather report (METAR) for KARG, issued at 1055, reported wind from 170 degrees at 8 knots, visibility 10 miles, clear sky, temperature 26°C, dew point 8°C, altimeter 29.89 inches of mercury. At 1045, the sun was at 108 degrees azimuth and 57 degrees altitude.
Flight Recorders
The Air Tractor was equipped with a Hemisphere GPS MD Intellistar CPU and a Del Norte Technology Intelliflow Controller. The devices were sent to the NTSB Vehicle Recorders Laboratory for data extraction. The Del Norte controller was not capable of recording data. The Hemisphere unit could record log and geolocation data on an internal compact flash card. The card was recovered and log files extracted using the vendor’s MapStar application. A flight track for the accident flight was recovered, including GPS date, time, latitude, longitude, and altitude for each recorded data point.
The Grumman was equipped with a Hemisphere Intelliflow Controller and a Del Norte Technology GPS Measuring Unit (GMU) I/F 2. The devices were sent to the same laboratory. The Hemisphere controller was not capable of recording data. The Del Norte GMU could record data on an internal CF card, but the unit was not equipped with the card.
Wreckage and Impact Information
The accident scene comprised two debris fields, one extending north and one extending west, both originating at the same point. The center point contained torn metal, paint chips, and fabric from both aircraft. The north debris field contained mostly Air Tractor components; the west field contained mostly Grumman components. Both wreckages came to rest in the rice field being dusted by the Grumman. A raised berm with two field service roads and an irrigation canal separated the north and south rice fields. Trees and bushes lined the canal.
The Air Tractor main wreckage was located north of the center point and included the fuselage, engine, propeller assembly, both wings, and the cabin, inverted. The propeller assembly separated and was found forward of the engine. The engine, propeller, and cowling showed evidence of heat and fire. The right wing remained attached, with crushing from the outboard tip inward. The right aileron separated and was found in the initial debris field. The right wing contained multiple tears consistent with propeller strikes. The left wing remained attached, with the outboard 11 feet bent down and wrinkled. The engine remained attached; the propeller assembly separated at the flange, but all five blades remained on the hub. Blades exhibited various damage including bending, tearing, and heat exposure.
The ground scar extended from the main wreckage 40 feet south to a berm. Various components were located in the debris field, including wing parts, instrument panel fragments, and personal effects. The empennage was 25 feet south of the end of a second ground scar, including the left horizontal stabilizer and elevator. The vertical stabilizer and rudder were separated. Paint transfer was observed on multiple components.
The Grumman lower left wing was located 35 feet north of the start of the debris field. A large area of dead vegetation consistent with fuel blight was found west of left wing fragments. The propeller assembly was located at the end of a ground scar; blades were labeled A through D and exhibited gouges, scratches, bending, and paint transfer. The main wreckage came to rest on its left side and included inboard portions of the left wing, empennage, fuselage, landing gear, and right wing. The fuselage forward of the cabin was crushed and fragmented. The empennage included horizontal stabilizers, elevators, vertical stabilizer, and rudder with various damage. The left horizontal stabilizer was bent up at the root and crushed; the elevator separated.
Medical and Pathological Information
An autopsy of the Air Tractor pilot was performed by the State Crime Laboratory in Little Rock, Arkansas, on May 24, 2012, as authorized by the Greene County Coroner’s office. The autopsy concluded the cause of death was multiple traumatic injuries, and the report listed specific injuries. The FAA’s Civil Aerospace Medical Institute performed toxicological tests on specimens collected during the autopsy (CAMI Reference #201200110001). Results were negative for carbon monoxide, cyanide, and ethanol. Testing of blood and urine revealed amlodipine (a calcium channel blocker heart medication) and yohimbine (typically found in over-the-counter dietary supplements).
Tests and Research
The Air Tractor was equipped with a FlightCell Pro, a device used to interface cellular telephones with the radio and intercom system. The Air Tractor pilot used this device to interface his cellular telephone with his helmet and radio system.
According to a local farmer, he had a telephone conversation with the Air Tractor pilot on the morning of the accident. The farmer did not recall the exact time but stated that when he became aware of the accident, he was concerned that the time frame for the call and the accident were similar. They discussed the new field the pilot was going to dust—the same field the pilot flew over at the time of the accident. They spoke for several minutes, and then the call disconnected, consistent with a dropped call. The farmer tried to call back and left a message. He did not speak with the pilot after the call was dropped.
Cellular telephone records from AT&T showed the pilot initiated a call to the farmer at 1045, with a seizure time of 8 seconds and a call duration of 4 minutes and 44 seconds. At 1050, the pilot’s phone received a call from the farmer, with a seizure time of 1 second and duration of 31 seconds. GPS data from the Air Tractor indicated the airplane departed at 1048:07 and the accident occurred at 1049:41.
Additional Information
Miles Flying Service stated that the airspeed of the Air Tractor at the end of a pass should be approximately 160 miles per hour. The Grumman pilot stated that his airspeed during his pass was approximately 135 miles per hour.
According to the operator of the Grumman, pilots are encouraged to conduct a survey of the field they will be working before flying their first pass.