What happened
On August 20, 2019, a Bell 407 helicopter, registration PT-YZF, operated by the Brazilian Federal Highway Police (PRF), was conducting an aerial patrol mission near Eunápolis, Bahia. The flight originated from Porto Seguro and was intended to land at a PRF station located along the BR-101 highway.
Upon arrival, the crew identified a paved area at the entrance of the station as a suitable landing site after an initial plan to land in a nearby field was abandoned due to the presence of livestock. During the landing sequence, the crew performed three 360-degree turns to survey the area. As the aircraft established a hover and initiated a left turn to align with the highway, the main rotor struck a fixed roadside sign. This impact caused a loss of control, leading the helicopter to strike the ground. The collision resulted in substantial damage to the aircraft, including damage to the rotor blades and the separation of the tail cone. The two pilots sustained light injuries, while the tactical operator remained uninjured.
The investigation
CENIPA's investigation focused on the suitability of the landing site and the crew's decision-making process. Investigators noted that the landing area was highly restricted, measuring approximately 10.80 meters at its narrowest point, which was smaller than the aircraft's total length of 12.61 meters. While the rotor diameter (10.66 meters) could technically fit within the width, the area lacked the safety margin required by the operator's manual.
The investigation also examined the possibility of aerodynamic factors, such as downwash, causing a piece of the sign—which showed signs of corrosion—to detach and strike the rotor. Furthermore, the investigation looked into the crew composition, noting that the tactical operator on board was at a "basic" qualification level and was performing duties alone that required supervision by an operational-level operator.
Findings
- Inadequate risk management regarding the use of a restricted landing area with nearby obstacles.
- Impaired decision-making and pilot judgment during the approach in a confined space.
- Reduced situational awareness due to the high cognitive demand of the complex landing maneuver.
- Managerial planning deficiencies regarding the assignment of a basic-level tactical operator to perform solo duties.