A Pawan Hans helicopter, with two pilots onboard, crashed near the Bombay High at 7:25 pm, defence ministry spokesperson Sitanshu Kar has said.
The helicopter was on a night landing practice on an oil rig, according to Kar.
A door of the helicopter has been located in the sea.
Two Indian Navy vessels are looking for the pilots, whose identities have not been made public yet.
The last known position of Pawan Hans Helicopter was 82 NM west of Mumbai.
A similar incident of Pawan Hans helicopter was reported on August 4, 2015 as well.
Pawan Hans is a private helicopter company providing travel services to places of pilgrimage, such as Vaishno Devi and Amarnath.
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