On July 2, 2022, about 0944 eastern daylight time, a Grumman G-164A, N8923H was substantially damaged when it was involved in an accident in Hopewell Township, New Jersey. The pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight.   The pilot was performing an aerial application flight over a nursery. As he pulled up at the end of a pass, he crossed over an area of trees and heard a “loud bang.” He attempted to maneuver the airplane to land in an open field; however, the airplane “ran out of altitude and airspeed” and impacted the ground.   Examination of the airplane revealed that during the impact sequence the engine and upper wing were separated from their respective mounting locations.   Postaccident examination of the engine revealed that when rotating the propeller, the drivetrain would rotate freely, and no binding was noted. All the engine cylinders were intact. The supercharger impeller was intact, but further examination revealed that it was not rotating when the propeller was moved by hand. The rear accessory/diffuser housing was removed to expose the supercharger impeller and no damage was noted on the external impeller blades; however, the rear splined impeller shaft ball bearing spacer (P/N 13814) and supercharger impeller (P/N 12788) splines were found to have sheared, allowing the impeller to freewheel.

Review of the airplane’s maintenance logs revealed that the engine had accumulated 7,598 total hours of operation and 1,031 hours since its most recent overhaul.