What happened
The incident occurred during a commercial aerial photography mission. The pilot was operating a helicopter over a lake, focusing on capturing images of a boat below. While maneuvering for the best angle, the pilot reported being temporarily blinded by direct sunlight. This visual impairment led to an inadvertent collision with unmarked power lines situated in the area.
Despite the impact, the pilot retained control of the aircraft and successfully navigated to nearby level terrain. The helicopter was landed safely without further incident during the flight phase. However, additional structural damage occurred to the airframe after the engine was shut down. This secondary damage was caused by an imbalance in the main rotor system following the initial collision.
The investigation
The investigation focused on the mechanical state of the aircraft post-incident and the pilot's account of the event. Examination confirmed that the primary impact involved the unmarked power lines. Post-shutdown analysis revealed that the main rotor had become imbalanced, leading to further damage to the airframe as the helicopter settled.
Findings
The collision was attributed to the pilot's temporary loss of vision due to sun glare. The lack of marking on the power lines contributed to the difficulty in avoiding them visually. The subsequent airframe damage was a direct result of the main rotor imbalance after the initial impact and shutdown.