What happened
On July 30, 2015, a Bell 206B helicopter, registration PT-YLD, departed from a rural area in São José dos Ausentes, Rio Grande do Sul, for a local sightseeing flight. The aircraft was carrying a pilot and three passengers.
Approximately five minutes into the flight, while on final approach to a landing site characterized by restricted terrain, the helicopter struck the branches of an araucaria tree. The impact damaged the lower right side of the cockpit bubble and caused the flight controls (pedals) to jam. The pilot attempted to continue the landing in the immediate vicinity. However, as the aircraft approached a hover before touchdown, an increase in torque caused the helicopter to rotate rapidly to the right. Due to the jammed pedals, the pilot could not counteract the yaw, leading the aircraft to strike the ground with its right skid and capsize. All four occupants escaped the crash without injury, though the aircraft sustained substantial damage to the rotor blades, fuselage, mast, and transmission.
The investigation
CENIPA's investigation focused on the flight profile and the pilot's decision-making during the approach to the irregular landing site. The investigation noted that the landing area was a small, uneven field (200m x 100m) surrounded by trees and rural power lines.
Investigators examined the pilot's recent flight history and found a low frequency of operations in the months preceding the accident due to other professional commitments. The investigation also identified that the aircraft was removed from the scene and the occurrence was not reported to authorities until five days later, which constituted a violation of Brazilian aeronautical regulations.
Findings
- Inadequate Pilot Judgment: The pilot executed an approach that did not follow recommended procedures for restricted areas, which suggest a high-angle approach with a steep descent profile, low speed, and low rate of descent to clear obstacles.
- Improper Decision-Making: The decision to land in a restricted area was based on an incorrect assessment of the operational risks involved.
- Loss of Proficiency: The pilot's low flight frequency may have degraded situational awareness and the ability to maintain the required proficiency for such complex maneuvers.
- Mechanical Consequence: The initial collision with the tree branches caused a failure in the tail rotor pitch control by jamming the pedals, making the subsequent rightward rotation uncontrollable.