Cessna 425, Menominee, Mich., Dec. 5, 2006–The pilot of the Conquest I told the NTSB that he landed and taxied onto the airport terminal ramp at Menominee normally. He brought the props into the Beta (reverse) range while taxiing to control speed. After he stopped on the ramp, he put the propellers back into Beta and backed the airplane about four to six feet to align with a parked airplane.
He set the parking brake then moved the power levers back to flight idle and the prop levers to feather. As he did this, the airplane started to move forward. He put the prop levers full forward and the brought back the power levers. As the aircraft continued forward, he pulled the fuel mixture handles to the shutoff position. The airplane hit the plate-glass-fronted building at about three or four mph. The pilot said the brakes and Beta were functioning properly. The airport manager said that the runways and ramp surfaces had thin patches of loose snow, and that the braking action was good.