What happened
On April 22, 2016, an Eurocopter AS350 B3, registration PT-YOY, was performing a short-duration flight near Parque da Pedra Branca, Rio de Janeiro. The aircraft had departed from an improvised landing site approximately 4.8 NM from Jacarepaguá Airport, carrying a pilot and two cargo masters. The mission involved transporting personnel and supplies to various clearings used for the assembly of electrical transmission towers.
As the helicopter approached the landing area for its final descent, the main rotor blades struck a metallic structure that had been left at the site following a previous flight. This impact destabilized the rotor system, causing a rotor blade to strike a steel cable attached to a winch motor located near the ground. The cable became entangled with the rotor blades and the rotor head, leading to the complete detachment of the transmission assembly from the rotor head. The pilot sustained minor injuries, while the two crew members were uninjured. The aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the operational procedures and the physical characteristics of the landing site. The investigation established that the operation was frequent and routine, yet it was being conducted in violation of Brazilian aeronautical regulations (RBHA 91). Specifically, the landing site lacked the necessary physical characteristics, such as proper clearance and safety buffers, required for such operations. Furthermore, there was no evidence that the operator had requested the establishment of a formal improvised landing area through the National Civil Aviation Agency (ANAC), nor were there records of measurements to define the area as a restricted landing site.
Findings
- The landing site contained obstacles in the safety, approach, and takeoff areas.
- The operation was conducted in disagreement with established safety regulations regarding the use of non-homologated landing sites.
- The operator failed to implement necessary measures to ensure the safety of the operation, the aircraft, and third parties.
- There was no designated ground person to monitor the landing area and ensure it was free of obstacles.
- The pilot did not visually identify the metallic structure prior to the collision.
- The aircraft was within weight and balance limits, and no mechanical failures of the engine or transmission were found prior to the impact.