20220528006269A

On may 28, 2022, at approximately 1340 CST, a 1977 Grumman American aviation; model: G-164B serial number: 178B; registered as N178LB, was destroyed when it crashed near Whiskerville, Arkansas. The pilot sustained fatal injuries. The airplane was operated as a title 14 code of federal regulations part 137 aerial application flight.

FAA and NTSB investigator(s) in charge (iic) dispatched to the scene on may 29, 2022 and found the aircraft wreckage confined to a small area immediately adjacent to a ditch running north to south. Ground signature indicated the aircraft impacted the ground in a flat attitude on the west side of the ditch, hopped over the ditch, and broke apart on the east side. A high-intensity fire ensued post-impact. All airframe components were located at the accident site and there was no evidence of in-flight breakup or collision with any other obstacle. The engine and propeller were separated from the airframe approximately ten feet from the aircraft. The wreckage was recovered from the accident site for future examination.

The aircraft was operated by a certificated part 137 operator based in light Arkansas. The owner of the business reported that the incident flight was the PIC?s first ?heavy load?.

Prior to the incident flight, the PIC flew several hours for training purposes. After the training flight, another pilot flew the airplane to calibrate and configure the onboard systems. After (4) four successful aerial applications, the other pilot returned to the base of operations and the incident PIC departed in the airplane.

The incident PIC flew the airplane to the field where the intended fertilizer operation would occur and performed several practice passes before returning back airstrip. The hopper was loaded with 2,500 pounds of fertilizer and the aircraft was fueled with three-quarters tank full of jet-a fuel and the incident PIC departed for the real application sortie.

Shortly before the incident, the incident PIC transmitted over the radio that, ?I?ve got to land this airplane?. After several unsuccessful attempts to contact the incident PIC, another pilot flew to the area and observed black smoke and the wreckage.

A witness, who lives about 1.5 miles from the accident site, reported that he heard the accident airplane flying nearby with a constant engine noise.

The engine suddenly either ?cut off? Or ?shut off,? And he heard no further engine noise. About 5 seconds later, he heard a loud impact followed by black smoke. The witness contacted first responders to report the accident.

Weather was not a factor.

Engine and propeller were disassembled and inspected.

Propeller inspection found no visible discrepancies that would prevent or degrade normal propeller

Operation prior to impact. All visible damage was consistent with high impact forces while rotating at low or no power (nts).

Engine inspection found a failure of the torque sensor gear (idler gear), located in the accessory gear box. This failure stopped the drive to the fuel control system, which stopped the rotation of the fuel pump and resulted in a fuel starvation issue. The inspection also found significant internal rust corrosion and severe pitting of the propeller shaft. Oil recovered from the engine exhibited an unusual crystaline formation and oil filter showed what appears to be black mold. Both oil and filter have been sent for closer examination.