What happened
On March 15, 2018, an AS350 BA helicopter, registration PT-HYV, operated by Maricá Air Taxi Ltd., was performing a mission to inspect electrical transmission lines in the municipality of Curralinho, Pará. The flight departed from an unpaved landing area toward Breves Aerodrome.
Approximately 15 minutes into the flight, while the pilot was attempting a hover out of ground effect (OGE) near the power lines, the aircraft's tail cone made contact with the transmission cables. In an attempt to maneuver the aircraft to the right to clear the obstacle, the tail rotor struck the wires, causing the rotor to fail. The helicopter subsequently crashed into a swampy jungle area. The pilot and three passengers sustained minor injuries, and the aircraft suffered substantial damage to the engine, rotors, structure, and transmission.
The investigation
CENIPA's investigation focused on the flight dynamics during the hover and the operational environment. Investigators noted that the pilot was attempting to maintain a hover only about 3 meters above the transmission lines. While weather conditions were generally favorable, the pilot reported a tailwind component during the maneuver.
The investigation also examined the pilot's technical background and the operator's oversight. Although the pilot was highly experienced in total flight hours, he had relatively limited experience specifically on the AS350 BA model. Furthermore, there was no evidence that the pilot had received specific training for transmission line inspection as required by the company's training manual, nor were there documented company procedures defining minimum approach heights for such high-risk maneuvers.
Findings
- Inadequate control inputs during the attempt to correct sinking and a nose-right tendency.
- Poor piloting judgment regarding the decision to perform an OGE hover with a tailwind in close proximity to obstacles.
- Low situational awareness due to the difficulty of visualizing the wires from the aircraft's position.
- Lack of specialized training for the specific mission profile (line inspection).
- Inadequate organizational oversight, as the company had not formalized procedures for approach heights or verified the completion of required specialized training for the crew.