What happened
On March 18, 2002, an SA 315B1 helicopter, registration I-FLAI, was performing a low-altitude aerial inspection and filming mission for electrical power lines near Broni, Italy. The crew, consisting of a pilot, an observer, and a camera operator, was flying approximately 10 meters above a medium-voltage line. While following a branch of the power line, the aircraft struck the intermediate cables of a perpendicular high-voltage line. The impact caused the helicopter to crash, resulting in the near-total destruction of the aircraft and three serious injuries to the occupants. The collision also severed two high-voltage cables and caused environmental damage due to fuel leakage.
The investigation
The ANSV investigation focused on the operational environment and crew dynamics during the mission. The investigation established that the aircraft was airworthy and the pilot held all necessary commercial licenses and type ratings. The weather conditions were favorable, with high visibility and no wind. Investigators examined the flight path, noting that the crew typically maintained a specific offset from the lines to facilitate filming. The investigation also looked into the lack of visual markers, such as balloons or painted pylons, on the electrical infrastructure in the area.
Findings
Several contributing factors led to the accident:
- Lack of crew coordination: The crew had only been working together for one week, which prevented effective communication and shared situational awareness.
- Task saturation: The pilot was heavily focused on maintaining a precise altitude and lateral distance from the target line, which diverted attention from scanning for obstacles.
- Limited observer utility: The observer was focused on inspecting the integrity of the insulators and cables, while the camera operator was focused on the monitor, leaving the pilot without sufficient external scanning support.
- Inadequate obstacle marking: The high-voltage lines crossing the flight path lacked any visible warning markers, such as brightly colored pylons or balloons.
- Failure to detect obstacle: The pilot failed to identify the perpendicular high-voltage lines before the collision occurred.