What happened
The pilot was conducting an agricultural application flight, specifically a swath run, when the incident occurred. During the operation, the pilot intended to climb over a power line located at the end of the designated swath. However, the aircraft encountered a tailwind gust which significantly degraded its climb performance.
Despite the reduced performance, the pilot attempted to clear the obstacle but could not obtain sufficient altitude to pass over the power line safely. Unaware that a lower power line existed in the immediate vicinity, the pilot elected to fly underneath the first line rather than aborting or climbing higher. The helicopter subsequently made contact with this lower line.
Following the impact with the power line, the aircraft lost control and descended rapidly to the terrain. Upon hitting the ground, the helicopter rolled over, resulting in a substantial accident.
The investigation
Post-accident examination of the aircraft confirmed that it had struck a power line during the descent phase. The physical evidence supported the pilot's statement regarding the encounter with a tailwind gust which compromised the ability to clear the initial obstacle.