On March 1, 1989, a Grumman G-164A (registration N8547H) was involved in an aviation accident near Riverdale, CA. Investigators recorded the probable cause as: The pilot's failure to maintain adequate visual scanning of the forward flight path while conducting aerial application operations, which resulted in the collision with power lines. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During an aerial application flight, the pilot completed a swath run and looked back to check flaggers. Upon looking forward again, the aircraft collided with overhead power lines.
What happened
The incident occurred during an aerial application mission involving crop dusting operations. The pilot had just finished completing a swath run over a designated field area. Following this maneuver, the pilot turned his attention away from the forward flight path to look back over his shoulder. This action was taken specifically to observe and verify the position of ground flaggers who were coordinating the operation.
After checking the rearward view, the pilot returned his gaze to the front. At that moment, the aircraft was in close proximity to overhead infrastructure. The pilot realized too late that the airplane was on a collision course with the wires. Despite the short notice, the aircraft struck the power lines immediately upon looking forward again.
Findings
The primary factor contributing to this accident was the pilot's temporary loss of situational awareness regarding obstacles in the flight path. By diverting visual attention rearward to check on ground personnel, the pilot failed to maintain a continuous scan of the airspace ahead. This lapse in observation resulted in the aircraft impacting the power lines before the pilot could react or alter the flight path.
Probable cause
The pilot's failure to maintain adequate visual scanning of the forward flight path while conducting aerial application operations, which resulted in the collision with power lines.