What happened
On May 10, 2011, a Schweizer S269C helicopter, registration I-TOMK, was engaged in aerial work involving the spraying of anti-parasitic substances on vineyards near Miane, Italy. The aircraft had been stationed on a concrete pad in the Combai hamlet since May 7, where it had been secured to ground anchors using synthetic ropes to protect it during its stay.
On the afternoon of the incident, the pilot decided to reposition the helicopter to clear the landing pad. After removing the protective covers from the aircraft, the pilot started the engine and attempted to take off. However, the pilot failed to remove the ground tie-down ropes. As the aircraft lifted from the surface, the tension on the remaining ropes caused a violent roll to the right. This movement forced the main rotor blades to strike the ground, causing the helicopter to capsize on its right side. The incident resulted in substantial damage to the main rotor, the fuselage structure, and the right skid, though no injuries were reported.
The investigation
The ANSV investigation examined the aircraft's maintenance history, the pilot's credentials, and the operational procedures used at the site. The investigation confirmed that the pilot was highly experienced, with over 6,300 total flight hours, and held valid commercial licenses. The aircraft's technical documentation and maintenance records were found to be in order.
Investigators noted that the pilot had personally performed the anchoring operation three days prior using only two ropes instead of the four recommended by the maintenance manual. The investigation also found that the concrete pad used for the operation was not an officially authorized heliport, though it functioned as an occasional landing site. Furthermore, the investigation found that the synthetic ropes lacked any high-visibility markers, such as "Remove before flight" streamers, which could have aided in their detection.
Findings
- The primary cause of the accident was the inadequate pre-flight checks performed by the pilot prior to takeoff.
- The pilot's failure to notice the tie-downs was likely due to complacency, stemming from the repetitive nature of performing simple, routine tasks.
- The lack of visibility of the anchoring ropes, which were not equipped with any red warning streamers, contributed to the oversight.
- The pilot had utilized only two anchor points rather than the four suggested by the manufacturer's manual.