The fate of the passengers is yet to be ascertained, ATC sources said.
The chopper belonging to private operator United Heli Charters had taken off from Juhu aerodrome here in the morning for Aurangabad, they said.
The accident occurred due to the chopper coming in contact with electric wires in a rural area of neighbouring Thane district, they said.
The Directorate General of Civil Aviation has rushed a team to the accident spot to investigate the cause of the mishap, a DGCA official said.