The Convair approached Campbell River with the weather just above minima (2-2,5 miles visibility, 400 feet broken ceiling and wind 110 degrees with gusts to 20 mph. The crew positioned the aircraft visually 2nm south of the airfield on a westerly heading preparatory to attempting an approach to the west. This would involve a right hand circuit flown above the broken south and west of the airport employing DME and ADF information. This improvised approach was not in accordance with published approach procedures under instrument conditions. After flying for 1 minute and 40 seconds the crew turned right. A few seconds after the captain expressed concern, the Convair struck a 1047 feet hill at 932 feet. PROBABLE CAUSE: “Non-compliance with the approved instrument approach procedure.”