Preliminary data based on the notification from the Brazilian authorities:
The aircraft took off from the Val de Cans / Júlio Cezar Ribeiro Aerodrome (SBBE), Belém - PA, to Breves Aerodrome (SNVS) - PA, at about 1119 (UTC), in order to carryout an operational mission with two pilots and a special equipment operator on board. During the en-route flight, the aircraft started flying on instrument conditions (IMC), above the cloud layer and, at about 1205 (UTC), when trying to return to visual flight conditions (VMC), a sudden maneuver was performed with a descending right turn. The rotation of the main rotor blades exceeded the limit of 390 RPM, reaching 493 RPM. There was a high vibration and the ELT was automatically activated. After the stabilization of the flight conditions, the aircraft proceeded to land on the destination.