A federal review of helicopter safety concerns launched after the deadly midair collision between a passenger jet and an Army helicopter in Washington, D.C., has identified a rash of concerns about the potential for a collision between air tour helicopters and planes at the Las Vegas airport.

By David Shepardson WASHINGTON (Reuters) -Three senior Democratic lawmakers on Tuesday urged the Federal Aviation Administration to address significant safety issues at Reagan Washington National Airport and maintain reduced air traffic after a series of troubling incidents.