The Pentagon must provide a realistic five-year spending plan because the current budget indicates that $138 billion in spending cuts are needed to meet President Bush's defense goal, a congressional report says. ``The Congress is faced with budget decisions that will have long-term implications, but without an updated five-year defense plan, it does not have the information necessary to fully assess alternatives,'' Comptroller General Charles Bowsher told the Senate Armed Services Committee on Thursday. Bowsher presented the General Accounting Office's assessment of defense spending. The investigative arm of Congress found that Bush's budget for fiscal 1991 includes a five-year program that projects spending of $1.5 trillion. That total is $212 billion less than the recent five-year plan that the administration prepared in fiscal 1989. However, the Pentagon has come up with only $74 billion in reductions from the 1989 projections. ``The Defense Department is still faced with decisions on how and where to make reductions of another $138 billion between fiscal 1992 and fiscal 1994,'' Bowsher said. The Pentagon, he said, has said the dramatic changes in Eastern Europe and the lessening Soviet threat to the West has made it difficult to decide where and how the reductions will be made. The comptroller general said the GAO does not expect the Pentagon to act hastily, but the decisions must be made soon. Bowsher suggested that the administration ``rethink our entire weapon system acquisition strategy,'' starting with the B-2 stealth bomber and the multiple-warhead MX nuclear missile. Repeating testimony he gave last week to the House Armed Services Committee, Bowsher suggested slowing down production of the costly stealth bomber until critical tests have been completed on the radar-evading aircraft. According to the GAO, the current schedule calls for spending more than $48 billion and ordering 31 bombers before critical performance tests have been conducted. The GAO also found that the Air Force plans to make an initial production decision on moving the MX missile from fixed silos to railroad cars before operational tests and evaluations have been done on the completed system. Shortly after the production decision, the Air Force plans to buy about 73 percent of the launch cars for the MX. Bowsher said that during the 1980s, the strategy of concurrent production and testing ``was designed to get systems in the field more quickly, but it often resulted in making extensive _ and expensive _ changes after the systems were fielded.'' The B-2 bomber and the MX rail-garrison program are following the same path, he said. Overall, the comptroller general painted a dire financial picture as he accused the Bush administration of spending projections that are ``the result of creative bookkeeping; they do not portray the real situation.'' According to Bowsher, the government is using surpluses in the federal trust funds for Social Security, highways and other divisions to cover up the real budget deficit. ``If we continue along this same path, we can expect the national debt to increase to $4.5 trillion by fiscal year 1995,'' Bowsher said. ``A debt of this magnitude would require annual interest payments of over $335 billion and would represent the largest single item in the federal budget.''