Summary: Comments were presented on the Federal Aviation Administration's (FAA) Air Traffic Control Computer Modernization Program. The comments were based on the extensive review conducted by the Senate investigations staff, the GAO analysis on the FAA reply to the Senate report, the GAO report on direct replacement of economically obsolescent and outmoded computers in the Federal Government, and lessons learned from GAO reviews of other large Government computer system acquisitions. FAA officials had proposed acquiring a new $2.8 billion en route computer system sometime in the 1980's. In its report, the Senate investigations staff found serious management and planning deficiencies in the en route air traffic control computer system. The Senate report contained recommendations to FAA. FAA was directed to report its actions on the recommendations to the appropriate committees by specific milestone dates. The FAA reply projects a 3- to 4-year milestone schedule for near term computer system improvements and analysis of direct replacement of the current computer system. This schedule is inconsistent with Senate committee concerns and recommendations. GAO found that it is costing the Government more to continue using outmoded computers it now owns than it would cost to lease new, up-to-date computers. To make an adequate and informed decision regarding near term direct replacement, GAO believes FAA needs to identify the full cost and all implications of simply maintaining the current system in terms of operations, maintenance, and software. GAO believes FAA should immediately initiate action to determine whether to buy a near term direct replacement system. With better assurance of adequate equipment support, FAA can then adequately consider and plan the air traffic needs of the 1990's and beyond. GAO found that FAA has not implemented the parts of the planning and resources allocation order that apply to policy, mission analysis, long range planning, and program performance and evaluation. GAO believes the Government clearly needs a chartered, Federal computer service center to provide managers with managerial and technical system development expertise. In addition, GAO has developed a structured management approach for computer systems development. This framework of principles and procedures represents essential elements of management control and are the product of extensive analyses of management weaknesses.