What happened
On April 20, 2004, a Schweizer Hughes 269C helicopter, registration I-MIKE, was conducting aerial spraying operations near Robella, in the municipality of Trino (VC). The pilot had departed from the Balzola airpark to perform agricultural spraying tasks. While flying nearly parallel to a medium-voltage power line, the aircraft's main rotor struck a 90-degree branch line that extended across the flight path. The impact severed the electrical cables and caused the helicopter to pitch up abruptly, leading to a subsequent impact with the ground from an altitude of approximately 5 meters. The pilot survived the accident without injury, but the aircraft was destroyed.
The investigation
The ANSV investigation focused on the circumstances surrounding the collision and the visibility of the electrical infrastructure. Investigators examined the flight path, the configuration of the power lines, and the pilot's prior reconnaissance of the area. The investigation confirmed that the aircraft was in a valid state of airworthiness, with all inspections and maintenance up to date, and ruled out technical failure as a contributing factor. Meteorological conditions at the time of the accident were reported as CAVOK (ceiling and visibility OK) with no wind.
Findings
- The primary cause of the accident was the collision between the helicopter and the power line.
- The causal factor was the pilot's failure to see the 90-degree power line branch while flying parallel to the main line.
- Although the pilot had performed a preliminary reconnaissance of the area, the specific branch line was not identified during that survey.
- A more thorough reconnaissance of the target area might have prevented the collision.