Bell UH-1F N4582D accident near Concrete, Washington

Probable cause

Arcing of an energized electrical power line to the external long line and the conduct of electrical energy to ground personnel.

NTSB analysis

The operator reported that the pilot was positioning a concrete bucket as an external load attached to a long line. At the end of the long line was a remote hook that was activated electrically from the cockpit. The pilot maneuvered the concrete bucket to the work location, which placed the long line 15-20 feet from a known energized power line. The energized electrical power line arced to the long line, and electrical energy was conducted down the remote hook circuit to the bucket, seriously injuring a construction worker who was ground handling the bucket.

Text from the NTSB. Open the NTSB docket for WPR12LA279 for the full record.