Transportation Security Act (ATSA) was enacted. Among other things, ATSA required that TSA provide for the screening of all checked baggage for explosives transported on flights departing U.S. commercial airports. Pursuant to ATSA, TSA deployed EDS and ETD equipment to screen checked baggage and identify potential threats from explosives. While TSA is responsible for operating or overseeing the operation of checked- baggage-screening equipment, TSA and S&T share responsibilities for the research and development of checked-baggage-screening technologies. During fiscal year 2006, most research and development functions within DHS, including TSA, were consolidated within S&T. After this consolidation, S&T assumed primary responsibility for the research, development, and related test and evaluation of airport checked- baggage-screening technologies. S&T also assumed responsibility from TSA for the TSL, which tests and evaluates technologies under development against TSA-established detection requirements. TSA continues to be responsible for: identifying the requirements for new checked-baggage-screening technologies; operationally testing and evaluating technologies in airports; and procuring, deploying, and maintaining technologies. TSA relies on S&T as the central coordination point to manage all work related to explosives that involve the TSL, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Sandia National Laboratories, and the Air Force Research Laboratory at Tyndall AFB. Deploying EDSs and ETDs According to TSA, since fiscal year 2001, TSA has made over $8 billion available to EBSP for activities related to checked-baggage screening. TSA uses two types of technology for checked baggage screening—the EDS and the ETD—at 462 U. S. commercial airports. EDS is used to identify suspicious bulk items or anomalies in checked baggage that could be explosives or detonation devices. In airports that have EDS, it is used for primary screening of checked baggage while ETD machines are used for secondary screening of checked baggage to help resolve EDS alarms. Additionally, at airports without EDS, the ETD machines are used for primary screening of checked baggage. See figure 1 for a photograph of an EDS machine and figure 2 for a photograph of an ETD machine. TSA deploys EDSs in multiple configurations, such as an in-line configuration and a stand-alone configuration. The in-line configuration integrates EDS with an airport’s baggage handling system—the conveyor system that sorts and transports baggage for loading onto an aircraft. EDS in stand-alone configurations are separate baggage screening units that are not integrated with a baggage-handling system and are typically located in an airport lobby although they may also be located in other airport locations. Checked baggage is manually loaded and unloaded on stand-alone EDS machines. As of October 2010, TSA had 2,297 EDS machines in its fleet, 1,938 of which were deployed at airports in the United States. At airports and terminals that do not use EDSs, ETD machines are used for primary checked-baggage screening. Typically, ETDs are used for primary screening of checked baggage at smaller airports. These airports typically do not have EDSs for primary screening of checked baggage. As of February 2011, TSA estimated that there were about 5,200 ETD machines used for the primary or secondary screening of checked baggage at U.S. commercial airports. TSA certifies the EDS it deploys to commercial airports for screening checked baggage, based on tests performed by the TSL. Specifically, TSA certifies that EDSs, alone or as part of an integrated system, can detect, under realistic operating conditions, the amounts, configurations, and types of explosive material which would be likely to be used to cause catastrophic damage to an aircraft, using requirements developed in consultation with experts from outside TSA. Furthermore, TSA periodically reviews threats to civil aviation security, including:  explosive material that presents the most significant threat to civil the minimum amounts, configurations, and types of explosive material that can cause, or would be expected to cause, catastrophic damage to aircraft in air transportation; and the amounts, configurations, and types of explosive material that can be detected reliably by existing or reasonably anticipated, near-term explosive detection technologies. Currently, TSA requires that EDSs undergo three types of testing— certification testing, integration testing, and operational testing—before it will purchase such equipment. First, TSA verifies that vendors’ explosives detection systems meet—that is, are capable of detecting in accordance with—the TSA established explosives detection requirements through the certification testing process. TSA’s decision to certify an EDS relies on the results of independent test and evaluation performed at the TSL. Prior to certification testing, TSL conducts preliminary evaluations of vendors’ EDS, known as certification readiness testing (CRT) and pre-certification, to determine the extent to which vendors are ready to enter certification testing. During CRT, TSL provides feedback to vendors on their EDS’s strengths and weaknesses in detecting explosives in order to help vendors make necessary adjustments to their detection software. Second, in addition to being certified that the EDS can meet explosives detection requirements, EDSs being deployed in an in-line configuration must also undergo integration testing. As part of this testing, machines deployed in an in-line configuration must demonstrate in a controlled environment that they can be successfully integrated within the baggage- handling systems used for checked baggage. Finally, following certification and integration testing, EDSs undergo operational testing in an airport setting to demonstrate that they can reliably and effectively function in a live airport environment. In 2005, TSA revised explosives detection requirements for the EDS; however, some number of the EDSs are currently operating at the levels to detect explosives as set forth only in the 2005 requirements. When TSA established the 2005 requirements, it did not have a plan that identified the appropriate time frames needed to deploy EDSs to meet the requirements. In January 2010, TSA again revised the EDS explosives detection requirements and plans to deploy EDSs meeting these requirements in a tiered and phased approach over a number of years. One tier of requirements consists of three levels and expanded the number and types of explosives that EDSs must detect. TSA is in the process of developing another tier of requirements, which will refine the amount (for example, minimum mass) of an explosive that can cause catastrophic damage to an aircraft. If TSA deploys EDSs that fully meet the one tier of the requirements, TSA must ensure that ETD machines are capable of detecting all of the explosives that EDSs will be able to detect to minimize any potential screening difference between the EDS and ETD. In November 2005, TSA revised its explosives detection requirements for EDS that had previously been established in 1998 by the Federal Aviation Administration. However, as of January 2011, some number of the EDSs in TSA’s fleet are configured to detect explosives at the levels established only in the 2005 requirements. The remaining EDSs are configured to detect explosives at 1998 levels. When TSA established the 2005 requirements, it did not have a plan with the appropriate time frames needed to deploy EDSs to meet the requirements. Standard practices for program and project management state that specific desired outcomes or results should be conceptualized, defined, and documented in the planning process as part of a road map, along with the appropriate steps, time frames, and milestones needed to achieve those results. Despite the absence of a plan, TSA officials stated that they must conduct testing to compare the false alarm rates for machines operating at one level of requirements to those operating at another level of requirements. According to TSA officials, the results of this testing would allow them to determine if additional staff are needed at airports to help resolve false alarms once the EDSs are configured to operate at a certain level of requirements. TSA officials reported that they had anticipated this operational testing was to be completed in March 2011. According to agency officials, TSA did not begin this operational testing immediately after the previous explosives detection requirements were established in November 2005 because the agency officials were aware at the time of a potential further revision of the requirements based upon a planned computer modeling effort to revise the detection standards that became known as Project Newton. TSA and S&T officials told us they had planned to use the results from Project Newton to further revise the explosives detection requirements to reflect the mass of an explosive that would cause catastrophic damage to an aircraft. Although Project Newton did not begin until 2007, TSA officials told us that they were aware of plans to further revise the requirements prior to the initiation of Project Newton and delayed operational testing in anticipation of the results of the computer modeling effort. As of April 2011, the EDS explosives detection requirements have not been changed based on results of the computer modeling because Project Newton is still under way, though TSA officials told us that they plan to use the results of Project Newton to later define a tier of the 2010 EDS requirements. (We discuss the status of Project Newton in more detail in app. II.) However, once it became apparent that the results of Project Newton would not become available to further revise the requirements, TSA did not establish a plan with time frames for completing the additional testing related to staffing. Standard practices for planning and project management suggest TSA should have defined the operational testing plan and milestones as part of a road map for assessing potential staffing changes when these EDSs were first deployed after the 2005 requirements were established. Establishing reasonable time frames to complete the operational testing could help TSA ensure it achieves its desired goal of activating EDSs capable of detecting the explosives established in the 2005 requirements in a timely manner. In January 2010, TSA revised the EDS checked-baggage explosives detection requirements partly in response to credible and immediate threats to civil aviation.