In a statement published on its website on August 4, the IAC revealed that the Mi-8АМТ RA-25640 helicopter collided with the external load of another helicopter on August 4 at 05:43 Moscow time. All 18 passengers onboard Mi-8АМТ RA-25640 were killed, the IAC said.

“According to the available information after takeoff the collision of rotor blades with an external load of another helicopter that had taken off earlier occurred. All 15 passengers and 3 crew members on board were killed, the rotorcraft was destroyed and partially burned down,” the IAC said in an organization statement.

“The Interstate Aviation Committee expresses the most sincere condolences to the families and relatives of victims,” the IAC added.

The BBC said the helicopter was reportedly taking workers to an oil station. The IAC did not immediately reply to an emailed question from Rigzone asking to confirm if the helicopter was carrying oil workers.

The IAC said it has formed an investigation team for the accident in accordance with Russian Aviation Legislation.