The Transportation Safety Board says soft ice getting into the engine caused a fatal RCMP helicopter crash during a training exercise near Cultus Lake on January 17, 2012.
One man, civilian RCMP Pilot David Brolin, died.
The ice caused a complete loss of power when the Eurocopter A-Star B3 was taking off following a snowfall, sending chopper back into the ground almost vertically.
The TSB investigation found the protective engine covers had not been installed when the helicopter was parked during a heavy snowfall, and the air intake system was not cleaned and dried prior to the engine starting.
That allowed soft ice to build up inside the air intake.
With 130 similar helicopters in use in Canada, Transport Canada has undertaken a review the engine inlet design.