The Trust Fund provides the primary source of funding for FAA and receives revenues principally from a variety of excise taxes paid by users of the national airspace system. The excise taxes are imposed on airline ticket purchases and aviation fuel, as well as the shipment of cargo. Revenues deposited in the Trust Fund are subject to congressional appropriations. In addition to Trust Fund revenues, in most years, General Fund revenues have been used to help fund FAA operations. As figure 1 shows, Trust Fund revenues have fluctuated since fiscal year 2000. A number of factors, such as external events and general economic conditions, contributed to this fluctuation in revenues because they affect the number of tickets purchased, the fares paid by passengers, the amount of fuel purchased, and the value of air cargo shipped. For example, revenues declined early in the decade because of a series of largely unforeseen events, including the September 11, 2001, terrorist attacks, that reduced the demand for air travel, resulting in a steep decline in airline industry revenue. Similarly, during the recent recession, Trust Fund revenues declined from $12.4 billion in fiscal year 2008 to $10.9 billion in fiscal year 2009, in part because of the 7 percent decline in domestic stic passenger traffic during that period. passenger traffic during that period. The Trust Fund is the primary source of funding for FAA’s capital programs and also provides funds for FAA’s Operations account. The capital accounts include (1) the Facilities and Equipment (F&E) account, which funds technological improvements to the air traffic control system, including the modernization of the air traffic control system, called the Next Generation Air Transportation System (NextGen); (2) the Research, Engineering, and Development (RE&D) account, which funds research on issues related to aviation safety, mobility, and NextGen technologies; and (3) the Airport Improvement Program (AIP), which provides grants for airport planning and development. In addition, the Trust Fund has provided all or some portion of the funding for FAA’s Operations account, which funds the operation of the air traffic control system and safety inspections, among other activities. Finally, the Trust Fund is used to pay for the Essential Air Service (EAS) program. In fiscal year 2010, FAA’s expenditures totaled about $15.5 billion, with Trust Fund revenues covering about $10.2 billion, or 66 percent, of those expenditures. As figure 2 shows, while total FAA expenditures grew about 60 percent from fiscal year 2000 through fiscal year 2010, the Trust Fund’s revenue contribution only increased 12 percent, while the contribution of general revenues from the U.S. Treasury has increased to cover a larger share of FAA’s operations expenditures. We discuss this change in more detail in the next section of this statement. Since the Trust Fund’s creation in 1970, revenues have in the aggregate generally exceeded spending commitments from FAA’s appropriations, resulting in a surplus. This surplus is referred to as the Trust Fund’s uncommitted balance—the balance in the Trust Fund that remains after funds have been appropriated from the Trust Fund and contract authority has been authorized. As of the end of fiscal year 2010, the Trust Fund’s uncommitted balance was about $770 million (see fig. 3). As figure 3 shows, the Trust Fund’s uncommitted balance has declined since reaching $7.35 billion in fiscal year 2001. This decline is largely a result of how Congress determines the amount of appropriations that should be made from the Trust Fund. Starting with the Wendell H. Ford Aviation Investment and Reform Act of the 21st Century (AIR-21) in 2000 and continuing with Vision 100, Congress has based FAA’s fiscal year appropriation from the Trust Fund on the forecasted level of Trust Fund revenues, including interest on Trust Fund balances, as set forth in the President’s baseline budget projection for the coming fiscal year. Each year’s forecast, and accordingly FAA’s appropriation, is based on information available in the first quarter of the preceding fiscal year. For example, the revenue forecast for fiscal year 2011 is prepared in the first quarter of fiscal year 2010. These revenue forecasts can be uncertain because it is difficult to anticipate, a year in advance, events that may significantly affect the demand for air travel or fuel usage, the fares that passengers pay, and other variables that affect Trust Fund revenues. In fact, as figure 4 shows, FAA’s forecasts of Trust Fund revenues (including both tax revenues and interest earned by the Trust Fund’s cash balance) have exceeded actual Trust Fund revenues (including interest) in 9 of 11 years, and in aggregate, these forecasted revenues have exceeded actual tax revenues by over $9 billion over that period. Accordingly, appropriations from the Trust Fund, which are based on these revenue forecasts, have also exceeded actual revenues, thus drawing the us drawing the uncommitted balance lower over the course of the last decade. uncommitted balance lower over the course of the last decade. Until recently, FAA generated a forecast for the President’s budget using models based on historical relationships between key economic variables, such as the growth rate of the economy, and aviation measures, such as passenger traffic levels and passenger fares, that affect Trust Fund revenues. The responsibility for forecasting Trust Fund revenues shifted from FAA to the U.S. Department of the Treasury (Treasury), which already had responsibility for other federal excise tax revenue forecasts, in fiscal year 2010. We have recently been asked by the Senate Commerce, Science, and Transportation Committee to examine the Trust Fund revenue forecasting process and how it might be improved; we expect to begin our review this year. The Trust Fund’s uncommitted balance, which exceeded $7.3 billion at the end of fiscal year 2001, dropped to $299 million at the end of fiscal year 2009—the lowest balance over the past decade. One of the greatest declines in the uncommitted balance occurred in 2002 following the sudden drop-off in aviation activity after the terrorist attacks of September 11. In addition, the declines in passenger traffic and aircraft operations and reduced fuel consumption in 2009 resulted in actual revenues to the Trust Fund that fell significantly below forecasted levels in fiscal year 2009 and an uncommitted Trust Fund balance that approached zero. In response, the fiscal year 2009 omnibus appropriation increased the general revenue contributions to FAA’s operations and decreased FAA’s appropriation from the Trust Fund by approximately $1 billion compared with what was originally outlined in the President’s fiscal year 2009 proposed budget for FAA. These additional general revenues kept the Trust Fund’s uncommitted balance from going negative, thereby avoiding budgetary challenges for FAA. As a result, general revenues accounted for 24 percent of FAA’s expenditures in fiscal year 2009 and reached 34 percent in fiscal year 2010 (see fig. 2). If the uncommitted balance is nearly depleted and actual Trust Fund revenues continue to fall below forecasted levels, there is a risk of overcommitting available resources from the Trust Fund—meaning revenues could be insufficient to cover all of the obligations that FAA has the authority to incur. A low uncommitted balance signals to FAA that limited revenues are available to incur new obligations while still covering expenditures on existing obligations and increases FAA’s challenge in moving forward with planned projects and programs. FAA officials have noted that they closely monitor the Trust Fund’s available cash and FAA’s obligations to ensure that enough cash and budget authority are available to cover FAA’s expenditures and obligations. In the short term, if there were a risk of overcommitting Trust Fund resources, FAA officials noted that they might delay obligations for capital programs if the Trust Fund did not have adequate revenues to cover those obligations without additional funding authorized and appropriated from the General Fund. According to FAA officials, they would first defer some capital program obligations so they could continue to fund operations, such as air traffic control and safety inspections. These actions would ensure that the agency did not incur obligations or expenditures in excess of the Trust Fund’s cash balance, which could potentially lead to a violation of the Antideficiency Act. Later this month, in the President’s budget, the administration will release its newest estimate of the Trust Fund’s fiscal year 2011 year-end uncommitted balance. Congress may choose to increase FAA’s authorized funding level in the near term to allow FAA to further develop NextGen, the new satellite- based air traffic management system that is designed to replace the current radar-based system. NextGen improvements include new integrated systems, procedures, aircraft performance capabilities, and supporting infrastructure needed for a performance-based air transportation system that uses satellite-based surveillance and navigation and network-centric operations. These improvements are intended to improve the efficiency and capacity of the air transportation system while maintaining its safety so that it can accommodate anticipated future growth. FAA has generally identified the NextGen capabilities that it plans to implement in the near term to midterm, through 2018. FAA’s capital investment is expected to be $11 billion to $12 billion through 2018. This cost does not include research, the airport and associated airfield improvements, or the aircraft equipage that is necessary to realize all benefits. In addition to FAA’s capital investment costs, FAA estimates that the equipage necessary to realize significant capabilities implemented through 2018 will cost in the range of $5 billion to $7 billion. Decisions about the long-term direction for NextGen (beyond 2018) have yet to be made, and two key planning documents—the NextGen Integrated Work Plan and Enterprise Architecture—contain a wide variety of possible ideas and approaches. Therefore, the costs of the system over the long term are uncertain, but have been estimated to be in the $40 billion range (combined public and private investment in ground infrastructure and avionics).