What happened
On August 22, 2011, at approximately 16:30 UTC, a Robinson R22 Beta, registration PT-HVX, was conducting a local flight over the Recreio dos Bandeirantes and Vargem Grande neighborhoods in Rio de Janeiro, Brazil. The flight, operated by Aeroclube do Brasil, had been underway for about 90 minutes when the pilot attempted a landing in an area of Vargem Grande.
Upon touchdown, the left skid sank into a muddy, waterlogged section of the terrain. This caused the aircraft to tilt sharply to the left. As the aircraft moved, the main rotor blades struck the ground, causing the helicopter to overturn onto its left side. The impact resulted in substantial damage to the main rotor, windshield, skids, and tail rotor. Both the pilot and the passenger escaped the incident without injury.
The investigation
CENIPA investigators examined the landing site and the flight sequence to determine the cause of the rollover. The investigation established that the landing area contained soft ground, mud, and standing water, with terrain depressions that tend to collect water during rainfall.
The analysis focused on the interaction between the aircraft's movement and the pilot's control inputs. Investigators looked into whether the sinking of the left skid triggered a sequence of movements that led to the loss of control during the landing phase.