Summary
On August 2, 2022, about 1146 central daylight time, an Air Tractor AT-502, registration N9184Q, was substantially damaged when it impacted terrain near Cheneyville, Louisiana. The commercial pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight.
History of Flight
The operator reported that the pilot was scheduled to disperse 7 loads of urea fertilizer over two jobs. He had completed the first job (5 loads) and was on the last load of the second job at the time of the accident. Data from the onboard SatLoc G4 GPS receiver showed that near the end of the flight, the airplane descended to about 11 ft mean sea level (msl) while flying east at 147 mph groundspeed. It then began a climbing left turn as airspeed decreased. The last recorded data point, about 1,300 ft west-southwest of the accident site, indicated the airplane was about 200 ft msl on a northeast heading at 128 mph groundspeed. Review of GPS data revealed that during the 24 times the pilot made an initial climbing left turn following a spray pass, the airplane reached an average altitude of about 200 ft msl.
A 1-minute video from a truck driving south on a nearby highway showed the airplane coming into view on the right side (west over trees bordering the highway). While climbing, it flew over the southbound lanes then northbound lanes. The airplane was lost briefly from view, then seen descending steeply. During the descent and immediately before impact, white smoke could be seen trailing the airplane.
One witness reported seeing the airplane bank left, then perform a “barrel roll” to the left, with a “quick puff” of white smoke at the start. The airplane then nosed down and impacted the ground; the smoke did not continue to ground contact. Another witness reported, “…the [airplane] went belly up and then rolled to head straight into the ground.”
Personnel Information
According to operator records, the pilot received 40 total hours of agricultural flight training in PA-18-150, PA-25-235, and 7GCAA aircraft. He also completed 5 hours of ground school and received a training record on November 10, 2021, specifying qualification as pilot-in-command in agricultural operations. Because his only agricultural flight training was in reciprocating engine-powered airplanes, he received additional training in a turboprop-equipped airplane. His logbook reflected 5 hours of dual training in an Ayres Corporation S2R-T34 over two flights in November 2021, and 4.9 hours in a Pilatus PC12.
Hired by the operator in mid-July 2022, the pilot was only allowed to disperse fertilizer at higher altitude than chemical dispersal. From July 17 to the accident date (excluding accident date), he flew the accident airplane about 19 hours, dispersing 61 loads of fertilizer. Excluding the accident date, he had logged 28.4 total hours in turboprop-powered airplanes.
The operator’s chief pilot reported that the pilot was taught proper use of BETA, Reverse, and propeller overspeed procedures, and that BETA was only to be used when the tailwheel was on the runway.
Aircraft Information
The airplane was powered by a 750 maximum continuous shaft horsepower Pratt & Whitney PT6A-34AG engine with a Hartzell 3-blade, single-acting, hydraulically operated, constant speed propeller with feathering and reversing capabilities. The mechanical low-pitch stop and hydraulic low-pitch stop settings were between 17.9° to 18.1°, and about 13°, respectively. The beta range (below hydraulic low-pitch stop) was from +13° to the mechanical reverse stop range between -7.5° to -8.5°.
The throttle quadrant on the left side of the cockpit contained a power lever, propeller lever, starting control lever, and friction knob. The upper portion of the power lever had a “thumb latch” required to be pushed forward to move the power lever aft of the idle stop into beta and further aft into reverse. A caution light placarded “PROP IN BETA RANGE” on the center instrument panel illuminated when a microswitch contacted the fuel control unit cam box lever.
The airplane was equipped with an electrically-operated stall warning system, a cellular phone, and a “Drift Finder” smoke system with an activation button on the lower portion of the control grip. The cellular phone and a GoPro camera with enclosed and two loose SD cards in the pilot’s vehicle were read out by the NTSB Vehicle Recorder Division.
Airframe maintenance records showed no entry indicating replacement of the stall warning horn since manufacture. Although operational testing of the stall warning horn was not part of the preflight inspection procedures per the FAA-Approved Airplane Flight Manual, the chief pilot reported he checked it as part of his preflight and believed it was operational. He also indicated that when he flew the accident airplane, he never experienced illumination of the “PROP IN BETA RANGE” bulb with the power lever at idle.
Wreckage and Impact Information
The airplane impacted an off-ramp of a highway on a magnetic heading of 164°, slid about 52 ft, and came to rest upright on a heading of 341° magnetic. The engine assembly with attached propeller separated from the structure and was located about 33 ft along and 7 ft to the right of the energy path. Heavy rain between the accident and NTSB arrival the next day was noted; a smell of fuel was present at the site. There was no evidence of in-flight or postcrash fire.
The hopper, cockpit, both wings, empennage, both horizontal stabilizers and elevators, and engine and propeller assembly exhibited extensive impact damage. The right wing showed far greater damage than the left. All primary and secondary flight control surfaces remained attached or were in the immediate vicinity, with no evidence of preimpact failure or malfunction of actuation mechanisms or control surfaces for roll, pitch, and yaw. The flaps were retracted and the flap droop system was continuous.
The stall warning vane switch separated from the leading edge and was found inside the left wing. The stall warning horn electrical circuit remained intact except for impact damage to an electrical wire at the wing root and a terminal of the horn, which remained installed in the displaced instrument panel. The horn exhibited slight abrasion on its face but did not operate during electrical testing; it was retained for NTSB Materials Laboratory examination.
Cockpit examination revealed a yellow plastic RainX bottle on the left side under the seat, resting against the 1.5-inch-diameter aileron torque tube. Above the torque tube was the elevator forward pushrod assembly (0.75 inch diameter). The RainX bottle trigger was separated and found among the wreckage; one side of the bottle exhibited a dent near the bottom about 2 inches in diameter.
Examination of the throttle quadrant, which was impact damaged and rotated from its normal position, revealed the power lever was in beta range and the anti-reverse lock plate assembly was impact damaged. The propeller control was midrange, the condition lever was at flight idle, and the friction was tight. The thumb latch of the power lever operated satisfactorily during postaccident testing. The throttle quadrant and “PROP IN BETA RANGE” bulb holder and bulb were retained for further examination.
The separated engine and fuel control unit, constant speed propeller governor, beta valve, and overspeed propeller governor showed no evidence of preimpact failure or malfunction that would have precluded normal operation.
Propeller examination revealed all blades had gouges on the leading edge. Blade No. 1 had a gentle slight forward bend; blades Nos. 2 and 3 were fractured at different locations and bent opposite the direction of rotation. The leading edge of blade No. 3 was twisted toward low pitch. An impact mark in the piston indicated a blade angle of 21°, above the mechanical low-pitch stop setting. There was no evidence of propeller assembly preimpact failure or malfunction.
X-ray images of the stall warning horn showed one group of strands unbundled with a separated strand visible. The filament of the “PROP IN BETA RANGE” bulb was intact and stretched. Examination of the throttle quadrant revealed one corner of the anti-reverse lock plate assembly bent upward with a corresponding contact mark on the aft side of the power lever.
Meteorological Information
According to the NTSB Meteorology Specialist’s Factual Report, there was no significant windshear identified below 15,000 ft.