On November 9, 2012, about 2007 central standard time, N619BA, a Fairchild Aircraft, Inc., SA227-AC, multi-engine airplane, sustained minor damage when the left main landing gear collapsed during landing at Minneapolis St. Paul International Airport (MSP), Minneapolis, Minnesota. The pilot was not injured. The airplane was registered to and operated by Bemidji Aviation Services, Inc. Night visual meteorological conditions (VMC) prevailed at the time of the accident and an instrument flight rules (IFR) flight plan had been filed for the 14 Code of Federal Regulations Part 135 scheduled cargo flight. The airplane departed Duluth International Airport (DLH), Duluth, Minnesota, about 1926 destined for MSP.The pilot reported that all three green landing gear indicator lights were illuminated before he performed an otherwise normal landing. About 50 to 100 feet after touching down on the runway, the left main landing gear collapsed. The airplane skidded off of the left side of runway and came to rest upright in the grass. A postincident examination of the airplane found two loose electrical connections to the hydraulic system. An overhaul teardown of the hydraulic shuttle valve showed the seat out of tolerance, cap safety wire holes damaged and a washer not to the current revisions. The washer also showed corrosion. An examination of the hydraulic power pack revealed a washer not to the current revision. The system operated normally after the electrical wiring was repaired, and the hydraulic power pack and shuttle valve were replaced. The operator reported that they have revised their life limitations on the hydraulic power pack so that it now complies with the instructions in the manufacturer's service letter.