What happened
On October 27, 2013, an AS 350 B2 helicopter, registration PT-HZQ, was conducting a local training flight near the Ilhéus Aerodrome in Bahia, Brazil. The flight, which included the pilot, a passenger, and an engineer, involved a series of low-altitude maneuvers, including hovering and approaches over a grassy area near runway 29. During the maneuvers, the aircraft entered a series of uncontrolled anti-clockwise turns. As the aircraft completed its fifth turn, it entered a descending trajectory with a rightward tilt, causing the main rotor blades to strike the pavement. The helicopter subsequently overturned on its right side. While the aircraft sustained substantial damage to the main rotor assembly, gearbox, horizontal stabilizer, and fuselage, the pilot and both passengers escaped without injury.
The investigation
CENIPA's investigation focused on the mechanical state of the aircraft and the operational circumstances of the flight. Investigators found that the hydraulic system was functioning correctly and that no mechanical anomalies were present to explain the loss of control. However, the investigation revealed that the hydraulic system's cut-off switch was found in the OFF position. The pilot admitted to a practice of not always performing hydraulic system tests before takeoff, feeling confident in operating the aircraft without the system. Furthermore, the investigation identified that the flight was an informal training session conducted without the operator's knowledge, involving a second pilot who lacked the required technical qualification for the AS 350 B2 type.
Findings
- The pilot was unable to recover the aircraft from the uncontrolled turns through control inputs.
- The hydraulic system was intentionally turned off, which likely contributed to the loss of control during low-speed maneuvers.
- The flight was conducted using informal training practices that bypassed established safety protocols.
- The crew composition included a pilot without the proper type rating for the aircraft.
- Organizational failures within the operator's management allowed for high levels of pilot autonomy, leading to risky and unmonitored operational practices.
- The lack of a formal Safety Management System (SMS) prevented the identification and mitigation of these operational risks.