What happened
On May 1, 2003, an AS 350 B2 helicopter, registration PR-YFF, operated by the Rio Grande do Norte Public Security and Social Defense Secretariat, was involved in an accident in Natal, Brazil. The aircraft was preparing to depart from a soccer field at the Military Police Headquarters for a flight to the State Administrative Center. However, the pilot deviated from the flight plan to perform maneuvers at the headquarters grounds.
During the takeoff, as the pilot increased power to achieve a vertical climb, the aircraft entered a sharp left-hand yaw. The pilot attempted to correct the heading but lost effective control, leading to a rapid leftward rotation and lateral drift to the right. In an attempt to regain control, the pilot reduced collective pitch to force an immediate landing. This resulted in a hard impact where the right skid struck the ground, causing the main rotor blades to strike the terrain. The aircraft eventually overturned onto its right side, sustaining severe damage to the main rotor, transmission, tail cone, landing gear, and various structural and hydraulic systems. \nTwo occupants sustained minor injuries, while the remaining two passengers were uninjured.
The investigation
CENIPA investigators examined the aircraft's maintenance history and the pilot's qualifications. The AS 350 B2 had undergone recent inspections and was considered airworthy. Technical inspections by HELIBRAS engineers found no mechanical anomalies in the flight components that could have contributed to the loss of control.
The investigation focused heavily on operational and human factors. It was noted that the flight was unplanned and lacked proper coordination. The pilot, who was also the commander of the Air Group, had placed an unqualified individual in the left seat and relegated an experienced pilot to a passenger seat. Furthermore, the investigation identified that the pilot's psychological state, characterized by high stress, anxiety, and an overconfidence that led to poor risk assessment, played a significant role in the accident.
Findings
- Improper flight maneuvers: The pilot used inappropriate pedal inputs during takeoff and failed to maintain directional control.
- Poor decision-making: The pilot incorrectly judged that reducing power to land was the appropriate response to the loss of control.
- Lack of flight planning: The mission was improvised, deviating from the filed flight plan and utilizing an unapproved landing site.
- Deficient crew coordination: The commander failed to utilize the experience of the other qualified pilot by placing him in the rear seat and placing an untrained person in the pilot seat.
- Organizational deficiencies: The Air Group lacked standardized training manuals, proficiency evaluation records, and formal operational procedures.
- Human factors: The pilot exhibited excessive confidence and an inability to properly assess risks during an unplanned mission.