LEXINGTON, Ky. — The lone air traffic controller on duty the morning Comair Flight 5191 crashed had only two hours of sleep before starting work on the overnight shift, a federal investigator said Wednesday. National Transportation Safety Board member Debbie Hersman said the controller had only nine hours off between work shifts Saturday. That was just enough to meet federal rules, which require a minimum of eight hours off between shifts, Hersman said. "He advised our team that he got approximately two hours of sleep," Hersman said. The controller, a 17-year veteran whose name has not been released publicly, worked...