Robinson R66 N766WC accident near St Jacob, Illinois

Probable cause

The pilot's in-flight collision with an unmarked wire during an aerial application flight; the wire lacked contrast with the surrounding environment.

NTSB analysis

The pilot was performing aerial application operations and stated that he aligned the helicopter to perform a pass along the edge of a wheat field. During the pass, he noticed a power line in front of him, but the helicopter was "too close to avoid [it]." He felt the helicopter mast contact the power line; the helicopter began to "shake" violently and then impacted the ground. The pilot stated that he had performed reconnaissance of the field before beginning the application to identify power lines and other obstructions; however, he had not seen the impacted power line during the reconnaissance nor during the application. The pilot stated that there were no mechanical malfunctions or failures of the helicopter. Postaccident examination revealed that the power line was a green copper wire approximately 1/4-inch in diameter. The power line pole at the southern edge of the field was within the tree line and the field vegetation was green; it is likely that this lack of contrast contributed to the pilot's inability to identify the wire.

Text from the NTSB. Open the NTSB docket for CEN19LA123 for the full record.