The two helicopters of the U.S. Park Police played an important role after the September 11 attacks on the Pentagon. The crews responded immediately, transporting injured personnel to hospitals. The helicopters served as a command and control platform, using their Forward Looking Infrared equipment to provide firefighters with intelligence about the scope and spread of the fire through the five rings of the structure, and taking over air traffic control for the Washington, D.C. airspace after the controllers at Washington National Airport had to evacuate due to thick smoke.