A Boeing Vertol BV-107 operated by Columbia Helicopters of Portland, Ore., crashed in August during a maintenance check flight in southern Montana, killing all three men aboard. Dead are pilot Rich Hernandez, 37; copilot Santi Arovitx, 28; and crew chief Kip Krigbaum, 45. The big twin-rotor helo, a civil derivative of the military’s CH-46, went down for as yet unexplained reasons about 9:30 a.m. in the Emigrant Peak area between Livingston, Mont., and Yellowstone National Park, officials said. The helicopter was preparing to participate in the ongoing fight against the Monument fire in the Absaroka Wilderness Area.