What happened
On December 15, 2015, a Robinson R22 Beta helicopter, registration PT-HVW, was conducting a flight instruction mission at Jacarepaguá Airport (SBJR) in Rio de Janeiro. The flight, operated by Ultra Pilot Escola de Aviação Civil Ltda., initially proceeded with a standard route segment before moving to a grass strip for takeoff and landing training.
After a successful landing, the student pilot, who was acting as the primary manipulator of the controls, attempted a vertical takeoff. During the initial phase of the takeoff, the aircraft began to tilt toward the left. The student pilot reported feeling a tendency to roll and attempted to use the collective to return the aircraft to the ground. The instructor attempted to intervene by lowering the collective to abort the takeoff, but the intervention was too late. The aircraft''s left skid caught on an uneven patch of ground, acting as a pivot point. This triggered a dynamic rollover, causing the main rotor blades to strike the terrain and the aircraft to capsize completely to the left. Both occupants on board escaped without injuries.
The investigation
CENIPA's investigation focused on the environmental conditions of the grass strip and the crew's coordination. Investigators found that the grass strip was in poor condition, characterized by high grass, medium-sized shrubs on the sides, and surface irregularities. Specifically, marks on the ground indicated that the left skid had struck a depression on the edge of the strip.
The analysis also examined the crew's performance. While the instructor was qualified, there was a lack of clear verbal communication regarding the transfer of controls during the critical final moments of the event. The investigation concluded that the aircraft was in an airworthy condition and that the engine and transmission were functioning normally. The investigation highlighted that the R22 model is particularly susceptible to dynamic rollover if the critical roll angle is exceeded.
Findings
- The primary cause of the accident was a dynamic rollover triggered by the left skid striking a surface irregularity.
- The grass strip infrastructure was inadequate for training due to high grass and uneven terrain.
- There was a failure in cockpit coordination, as there was no verbal transfer of control between the student and the instructor during the emergency.
- The instructor's corrective action was delayed due to potential errors in command application and judgment during the initial moments of the roll.
- The aircraft sustained substantial damage to the engine, transmission, main rotor, tail rotor, windshield, left door, and tail cone.