ERA23LA332 · Bell 47G-5

The pilot of the aerial application helicopter departed from a chemical truck staging area to a nearby corn field, where he was performing his eighth application flight of the day. There were no witnesses to the accident and the pilot was fatally injured. The accident site was located near the edge of the cornfield, which was bordered by a road, trees, and a powerline. The helicopter’s spray boom and one landing gear skid were separated from the fuselage and found in a tree entangled with the power lines. The helicopter’s fuselage, engine, and fuel tanks were consumed by a postimpact fire. Given this information, it is most likely that the helicopter impacted the powerline while maneuvering at low level above the corn field. The pilot had received training about 13 years before the accident to act as pilot-in-command of aerial application operations. The training program included a skills test to demonstrate safe low-level maneuvering and how to approach the working area to locate obstacles. The extent to which the pilot had conducted a preflight assessment of the corn field for obstacles and was aware of the location of the wires could not be determined. A postaccident autopsy of the pilot’s remains identified cardiovascular disease that would have increased his risk of experiencing a sudden impairing or incapacitating cardiac event, such as arrhythmia, chest pain, or heart attack. The autopsy did not provide specific evidence that such an event occurred; however, such an event would also not leave evidence readily identifiable by an autopsy if it occurred shortly before death. Therefore, whether the pilot was incapacitated to some degree by a cardiac event that preceded the wire strike could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset