The pilots died in the accident involving a AW609 til-rotor – described by the company on its website as a “game changer” – prototype in the northern Piedmont region.
Witnesses told Ansa that the plane exploded before crashing into a corn field near the city of Vercelli.
The aircraft, which combines the vertical takeoff of helicopters with the fixed-wing and rotary-wing flight of aeroplanes, had taken off from Vergiate, the Lombardy town where one of the five AgustaWestland plants in Italy is based.
Magistrates in Vercelli have opened an inquiry to establish the cause of the accident.
The company, which is owned by the Italian defense contractor Finmeccanica, said it was working closely with investigators and expressed its condolences to the families of the pilots.