Furloughs push U.S. air traffic system near 'yellow' warning NEW YORK (Reuters) - The U.S. air traffic control system is close to hitting a "yellow" alert level as people who keep radar and other equipment running remain out on furloughs due to the government shutdown, the head of the controllers union said on Thursday. Air travelers would face lengthy delays if a radar unit or other equipment broke at a major U.S. airport because no one is on duty to fix it, Paul Rinaldi, president of the National Air Traffic Controllers Association (NATCA), told Reuters in an interview. The system's safety has not deteriorated, Rinaldi said. But "we're getting to yellow" in facing a major disruption from equipment failure that could foul thousands of flights, particularly if there was bad weather. Yellow indicates caution and is not based on a risk scale used by aviation regulators. Failure could affect big U.S. carriers such as Delta Air Lines, United Airlines, American Airlines, Southwest Airlines Co and others. "The impact will come as we continue to run this system without our full team out there," he said. "We're not doing maintenance on radar equipment" or communication equipment. "As that breaks down, that will limit the amount of airplanes we put in certain areas," he said. Rinaldi's statements on the 10th day of the government shutdown coincided with a rally in Washington, D.C., by aviation groups raising concern about the Federal Aviation Administration's continuing furloughs of "non-critical" staff. The FAA said its top concern is safety and that it has contingency plans under which "controllers and other essential employees will continue working in order to maintain the safety of the national airspace system." The nation's 14,600 air traffic controllers are working through the budget crisis, but about 2,800 NATCA members, including support specialists and engineers, are not working, the union said. "With fewer FAA employees on the job, some non-critical inspections, registrations and certifications will take longer," said Jean Medina, spokeswoman at Airlines for America, a trade group of U.S. carriers. She said the group believes safety will not be compromised. The furloughs also have affected the ability of planes and pilots to complete their certifications and to register aircraft sales, holding up deliveries of new planes to the market. The FAA on Tuesday said it would begin recalling 800 of those workers this week to help end the delays. Another 1,600 remain furloughed. Overall, the agency has furloughed 15,500 workers, or about one-third of its 46,000 employees. Rinaldi said a radar failure at John F. Kennedy International Airport in New York could foul thousands of flights, leading to many hours of delay for passengers. He said the FAA likely would recall workers to fix the problem, but the time to fix it would be much longer than normal. Equipment failure also could close runways, or even airports, if instrument landing systems were affected. In bad weather, pilots rely on such instruments to guide them through low clouds to the runway. Also, flight charts that are normally updated every month or two are not being altered to reflect changes in the system, meaning the charts are increasingly out of date, Rinaldi said. Reporting by Alwyn Scott; Editing by Leslie Gevirtz