On July 4, 2000, a Bell 47G (registration N30DP) was involved in an aviation accident near Haines, OR. Investigators recorded the probable cause as: The pilot's misjudgment of descent rate and delayed level-off during a low-level spray run over hilly terrain, which resulted in skid impact with the ground. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter overturned after skids struck terrain while the pilot misjudged descent rate during a low-level agricultural spraying run over hilly ground.
What happened
The pilot was conducting agricultural crop dusting operations in an area characterized by uneven, hilly topography. To execute the required spray passes, the aircraft had to traverse this difficult terrain at low altitude. During one such approach, the pilot misjudged the rate of descent and failed to level the aircraft off in time. Consequently, the helicopter's skids made contact with the ground. The impact caused the aircraft to roll over at least three times.
The investigation
Post-accident examination revealed no anomalies with the helicopter's powerplant or its flight control system that would have hindered normal operation. The mechanical systems functioned as designed throughout the incident.
Probable cause
The pilot's misjudgment of descent rate and delayed level-off during a low-level spray run over hilly terrain, which resulted in skid impact with the ground.