What happened
On March 18, 2016, an AS 350 B2 helicopter, registration PR-HCT, was engaged in wildfire suppression operations in the southwest sector of Caracaraí, Roraima. The aircraft, operated by IBAMA, was performing a second landing at a restricted area to deploy firefighters to a nearby fire site.
During the final approach, the aircraft experienced an inadvertent sink. The main rotor and tail rotor struck trees approximately 15 meters in height. Following the impact, the pilot experienced a slight right yaw but managed to maintain control of the aircraft and completed the landing approximately fifteen meters from the initial impact site. Despite the substantial damage to the rotor blades, all six occupants (three crew members and three firefighters) escaped the aircraft without injury.
The investigation
CENIPA's investigation focused on the flight dynamics and cockpit environment during the critical phase of flight. Investigators analyzed the aircraft's maintenance logs, which showed the engine torque had exceeded limits (OVER LIMIT) approximately 19 seconds before the engine was shut down, a result of the excessive torque applied immediately following the rotor strike.
While the pilot suggested that windshear might have caused the sudden descent, meteorological data from the nearest station was too distant to confirm this. The investigation also examined the cockpit's operational environment, noting that the commander was providing informal flight instruction to the co-pilot at the moment of impact. Furthermore, investigators reviewed the lack of Crew Resource Management (CRM) training and the absence of the General Operations Manual (MGO) on board.
Findings
- The flight was conducted with a tailwind and a low approach slope.
- Inadequate cockpit coordination occurred because the commander's informal instruction to the co-pilot distracted the crew during a critical phase of flight.
- The crew's decision to proceed with the landing despite the tailwind and suboptimal approach angle contributed to the event.
- A lack of CRM training hindered the crew's ability to maintain situational awareness and manage the aircraft's parameters effectively.
- Organizational factors, including a lack of standardized selection processes for the pilot pool and inadequate management supervision, allowed for the practice of unstandardized, informal flight procedures.