On July 31, 1993, a Bell 47G-3B (registration N8480E) operated by Ambrose, Walter J. Jr. was involved in an aviation accident near Clarinda, IA. Investigators recorded the probable cause as: THE COMMERCIAL PILOT'S FAILURE TO MAINTAIN ADEQUATE CLEARANCE FROM OBSTACLES DURING AERIAL APPLICATION MANEUVERS. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A commercial pilot conducting aerial application reported impacting power lines with the skids during climbout; the helicopter came to rest inverted.
Incident Overview
A commercial pilot involved in aerial application operations reported an accident that occurred during a spray run. The pilot had been conducting maneuvers over flat terrain and had assessed the field to locate obstacles before initiating the first spray run from east to west.
Sequence of Events
During the second spray run, as the helicopter approached the east end of the field, the pilot was verifying the existence and location of power poles and looking for power lines. While climbing out at the east end of the field, the skids of the helicopter impacted the power lines. Subsequently, the helicopter came to rest inverted.
Pilot Actions
The pilot stated that he had assessed the field for obstacles prior to beginning operations. The accident occurred when, during the climbout phase of the second spray run, he was focused on confirming the position of power poles and searching for power lines.