What happened
On July 18, 2011, a Robinson R-22 helicopter, registration PR-RCE, was conducting a training flight from Campo de Marte in São Paulo to an unregistered helipad at Morro do Catunum, in Cajamar, Brazil. The flight was being operated by Golden Fly Escola de Aviação Civil Ltda. and carried a pilot and one passenger, who was also an instructor from the same school.
During the training session, the pilot was performing maneuvers at an altitude of no more than five feet above the ground. The aircraft moved backward and lost altitude, causing the left skid to make contact with the terrain. In an attempt to recover, the pilot applied upward collective and moved the cyclic to the opposite side of the roll. This action triggered a dynamic rollover to the left, using the left skid as a pivot point. The helicopter rolled rapidly on its longitudinal axis, causing the main rotor blades to strike the ground. The impact resulted in the sudden stoppage of the engine and caused substantial damage to the main transmission, windshield, fuselage, tail rotor, and left skid.
The investigation
CENIPA's investigation focused on the aerodynamic phenomenon of dynamic rollover and the training environment. Investigators found that the flight school's training curriculum did not explicitly include the study of dynamic rollover or the specific recovery techniques recommended by the manufacturer. The Pilot Operation Handbook for the R-22 specifies that the most effective way to stop a dynamic rollover is to rapidly reduce the collective, rather than applying cyclic in the opposite direction.
The investigation also examined the operational context, noting that the presence of a colleague on board may have contributed to a degradation of the pilot's attention. Furthermore, the training area contained natural obstacles that increased the difficulty of the maneuvers. The investigation established that the pilot was properly licensed and the aircraft was airworthy and within weight and balance limits.
Findings
- The primary cause of the accident was a dynamic rollover triggered by the left skid contacting the ground.
- The pilot's recovery attempt—applying cyclic in the opposite direction of the roll—exacerbated the movement instead of mitigating it.
- The flight school's training program lacked specific instruction on the theory and practical recovery procedures for dynamic rollover.
- There was a lack of adequate managerial supervision regarding the selection of training areas free from obstacles.
- A decrease in situational awareness and attention was noted, potentially influenced by the relaxed atmosphere of having a colleague on board.
- The pilot was performing maneuvers at an altitude of less than five feet, contrary to manufacturer recommendations for avoiding such incidents.