The General Accounting Office warned the FAA that unless it makes better plans to replace the 5,000 air traffic controllers expected to retire over the next five years, there might be a shortfall that could affect the safety of the ATC system and increase air traffic delays. The GAO agreed with the National Air Traffic Controllers Association that it takes three- to five years to train a full-performance-level controller, and the FAA training academy has had failure rates as high as 50 percent. The FAA will be hit particularly hard in the next few years because many of the controllers hired in the early 1980s to replace controllers fired by President Reagan after the 1981 Patco strike are nearing the mandatory retirement age of 56.