All four people aboard a small jet were killed Thursday morning when it crashed shortly after taking off from a small airport in Connecticut, officials said. The jet took off just before 10 a.m. from the Robertson Airport before crashing into the building at Trumpf Inc., a manufacturing company, Farmington Police Lt. Tim McKenzie said. “It appears there was some type of mechanical failure during the takeoff sequence that resulted in the crash behind us,” he said. The plane, a Cessna Citation 560X, was headed to Dare County Regional Airport in Manteo, North Carolina, the Federal Aviation Administration said. Two pilots and two passengers aboard the plane were killed, McKenzie said. Their names were not immediately released. The crash set off chemical fires inside the Trumpf building, Gov. Ned Lamont said. Everybody who was inside the Trumpf building has been accounted for and there were no serious injuries, McKenzie said …