GRUMMAN ACFT ENG COR-SCHWEIZER G-164B

Full Narrative

On July 1, 2025, about 1145 central daylight time, a Grumman G-164B airplane, N8834H, was substantially damaged when it was involved in an accident near Lockport, Louisiana. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight.
The pilot reported that on the morning of the accident he flew two previous aerial application flights in the airplane without issue. Before the first flight of the day, the airplane contained about 60 gallons (360 lbs) of fuel. The outside air temperature and humidity had increased since his first two flights and he estimated that the temperature at the time of the accident was 93°F. The pilot sprayed a few fields while enroute to the final field, and estimated that he had about 35 gallons (210 lbs) of fuel and about 160 gallons (1,334 lbs) of liquid applicant in the hopper before arriving to the final field. He descended into the target field and completed one spray pass. As he approached the end of the field, he increased airplane pitch but “noticed the plane not climbing as normal” despite all the engine gauges depicting normal indications. The airplane descended as he approached a highway, but he did not want to dump the hopper over the highway or the adjacent bayou. The airplane cleared a set of powerlines next to the highway, landed hard in a field, and then nosed over.
The FAA inspector reported that the airplane came to rest inverted in a field. The fuselage and empennage sustained substantial damage. The engine remained partially attached to the firewall. The upper and lower wings remained attached to the fuselage and sustained leading edge damage.
Postaccident examination revealed that the throttle, mixture, and propeller control levers remained in place and undamaged in the cockpit. The engine controls were positively traced from the cockpit, down the left side of the fuselage and through the firewall. The control ends were impact separated from their connection points on the carburetor and propeller governor. The control levers were actuated fore and aft and moved freely. The propeller control exhibited slight binding due to impact damage and bends in the control cable. When the propeller was rotated manually, normal thumb compression and suction was obtained at each cylinder. The crankshaft and all accessories rotated smoothly and freely when the propeller was rotated manually, and the crankshaft and cam ring operated normally. Postaccident examination of the airframe and engine did not reveal any mechanical malfunctions or failures that would have precluded normal operation.
The most recent weight and balance calculation showed the empty weight was 4,252 lbs. A placard in the cockpit indicated that the maximum gross weight was 5,200 lbs. According to the maintenance records, the airplane’s maximum hopper capacity was increased from 2,000 lbs to 2,800 lbs in 2017 in accordance with CAM 8.10-3(e).
The estimated weight of the airplane at the time of the accident was about 5,996 lbs. The reported hopper weight (1,334 lbs) was within the airplane’s special purpose load (hopper capacity) limitation of 2,800 lbs.
The calculated density altitude for the accident flight was about 2,353 ft.