An engine malfunction led to the helicopter crash that claimed the lives of a pilot and CTV cameraman in August, the Transportation Safety Board has determined.
Pilot Roger Belanger and CTV's Hugh Haugland were approaching the airport after filming the aftermath of a tornado in Mont Laurier, 225 kilometres northwest of Montreal.
A small part - the size of a washer - in one of the aircraft's exhaust valves broke during the helicopter's approach into the airport, causing one of the cylinders to stop functioning and the engine to lose power.
Belanger was attempting to land the chopper safely while flying with reduced power, when the aircraft hit a power line, flipped over and crashed.