What happened
On November 24, 2009, a Bell 206B helicopter, registration PT-YEG, was conducting operational training for rappelling maneuvers at the Civil Police Academy (ACADEPOL) in Florianópolis, Brazil. The flight was intended to train 20 students, but because the originally designated aircraft (an H350) was still in transit, the pilot decided to use the available PT-YEG to avoid delays.
The pilot, who lacked previous experience conducting rappelling operations in this specific aircraft model, had already experienced control difficulties during an initial training flight. Despite noting that the aircraft's controllability was compromised, the pilot agreed to a second attempt involving only one rappeller. During this second maneuver, while the aircraft was hovering at an altitude of approximately 4 meters, a crew member moved from the left to the right side of the cabin to observe the descent. This sudden movement likely shifted the center of gravity and caused a cyclic control input to the left. Consequently, the helicopter entered an uncontrolled 440-degree right turn and struck the ground, causing the tail rotor to impact the terrain and sever the tail cone. The landing gear struck the soft grass, which prevented the aircraft from tipping over and striking the main rotor.
The investigation
CENIPA's investigation focused on the decision-making process and the operational environment during the training. Investigators examined the aircraft's maintenance records, which showed the 100-hour inspection was up to date, and the pilot's qualifications, which were valid. The investigation also looked into the organizational safety culture, noting a lack of flight safety oversight and the absence of a designated Flight Safety Officer within the organization. Furthermore, the investigation highlighted that no ambulance was present at the training site during the incident.
Findings
- The pilot's judgment was a primary contributing factor, as the decision to proceed with a mission in an unfamiliar aircraft without specific training led to the loss of control.
- The pilot's lack of experience with rappelling maneuvers in the Bell 206B model contributed to the accident.
- Inadequate management supervision allowed for the unauthorized substitution of the aircraft type for the training mission.
- The sudden movement of the crew member caused a control input that triggered the uncontrolled rotation.
- The organization lacked established flight safety prevention mechanisms, such as the use of Prevention Reports (RELPREV).