An Era Aviation de Havilland Dash 8-100, registration N886EA performing flight 7H-874 from Anchorage,AK to Homer,AK (USA) with 12 passengers and 3 crew, was climbing through 12,000 feet out of Anchorage when the aircraft entered an uncommanded roll to the left and began to lose altitude. The crew was able to regain control of the aircraft at about 7,000 feet and returned to Anchorage for a safe landing about 40 minutes after departure.