What happened
On 21 January 2013, a Bell 206B helicopter, registration PR-JBN, was conducting a low-altitude flight over a residential area in the Comunidade Jardim Rincão, São Paulo. The flight, operated by Helimarte Táxi-Aéreo Ltda., was intended to survey specific terrain near the Campo de Marte Aerodrome.
During the final segment of the flight, the pilot attempted to reposition the aircraft to allow passengers to better view terrain that had passed to the left. Instead of performing a standard left turn, the pilot chose to fly the aircraft backwards. During this maneuver, the helicopter entered a critical aerodynamic condition due to the aircraft's orientation relative to the prevailing winds. This resulted in a loss of lift and a subsequent descent. The aircraft collided with low-tension electric wires, which became entangled in the main transmission, before striking the roofs and concrete slabs of three houses.
The crash resulted in one fatality (the pilot) and two serious injuries among the passengers, while a third passenger sustained minor injuries. The aircraft suffered substantial damage, including fractured rotor blades and structural damage to the tail boom and cabin.
The investigation
CENIPA's investigation focused on the aerodynamic state of the aircraft and the pilot's decision-making. Technical analysis of the engine, fuel, and hydraulic fluids confirmed that all mechanical systems were operating normally prior to the impact. The investigation also examined the impact dynamics, noting that the collision with the electric wires caused the wires to twine around the main transmission.
Investigators analyzed the aircraft's performance relative to its weight and the environmental conditions. It was determined that the helicopter was at its operational limit for a hover out of ground effect (OGE) given its weight. The investigation also noted that the pilot's attempt to recover from the loss of lift—applying forward cyclic and downward collective—was unsuccessful due to the low altitude and proximity to the ground.
Findings
- Pilot judgment: The pilot chose to fly the aircraft backwards to quickly reach a new visual position, disregarding a safer left-turn maneuver. This maneuver placed the aircraft in a critical wind quadrant (winds from 20º to 210º) that the manufacturer advises avoiding.
- Flight planning: There was a lack of pre-flight coordination or safety briefings with the passengers regarding the flight's objectives and safety protocols.
- Operational altitude: The pilot's failure to maintain a minimum safe altitude over high-density residential areas hindered the ability to execute an effective recovery maneuver once the loss of lift occurred.