GAO report, dated September 2009: A National Strategy and Other Actions Would Strengthen TSA’s Efforts to Secure Commercial Airport Perimeters and Access Controls – “Although TSA has implemented activities to assess risks to airport perimeters and access controls, such as a commercial aviation threat assessment, it has not conducted vulnerability assessments for 87 percent of the nation’s approximately 450 commercial airports or any consequence assessments. As a result, TSA has not completed a comprehensive risk assessment combining threat, vulnerability, and consequence assessments as required by the NIPP. While TSA officials said they intend to conduct a consequence assessment and additional vulnerability assessments, TSA could not provide further details, such as milestones for their completion. Conducting a comprehensive risk assessment and establishing milestones for its completion would provide additional assurance that intended actions will be implemented, provide critical information to enhance TSA’s understanding of risks to airports, and help ensure resources are allocated to the highest security priorities.”