It is a performance-based  surveillance technology using GPS-enabled satellites to produce flight  information, such as an aircraft’s location and velocity, and according to  FAA, it is more precise than radar. Using this readily available public information, we  were able to track various kinds of military aircraft that were equipped  with ADS-B transponders. DOD and FAA Have Identified Security and Mission Risks Related to ADS-B Out Technology but Have Not Approved Any Solutions to Mitigate Them

Since 2008, DOD and FAA have identified a variety of ADS-B- related  risks that could adversely affect military security and missions. ADS-B technology better enables individuals and  groups to track flights in real time and use computer programs to log  ADS-B transmissions over time. According to NORAD command officials, the command relies on  information from FAA radars to monitor air traffic in the national airspace  system. the electronic warfare and cyber-attack concerns and the effect on  sensitive defense missions that DOD has identified. Furthermore, unless FAA  and DOD focus on the security risks of ADS-B and approve one or more  solutions in a timely fashion, they may not have time to plan for and  execute any technical, programmatic, or policy actions that may be  necessary before all of DOD’s aircraft are required to be equipped with  ADS-B technology on January 1, 2020. DOD Has Achieved Mixed Implementation of Key ADS-B Tasks Directed in 2007

Of the eight tasks associated with the implementation of ADS-B Out  technology in the 2007 DOD NextGen memorandum—issued by the  Deputy Secretary of Defense to ensure that the NextGen vision for the  future national airspace system met DOD’s requirements and the  appropriate management of DOD’s resources—DOD has implemented  two, has partially implemented four, and has not implemented two. Specifically, we found that DOD has implemented the following two tasks:
Establishing a Joint Program Office. DOD had not taken significant action or fully implemented the following  two actions:  Integrating NextGen requirements into plans and policies: The  Secretary of the Air Force, in executing the service’s responsibilities  as Lead Service, did not integrate the needs and requirements of  DOD components related to ADS-B into cohesive plans and policies  for inclusion in NextGen joint planning and development, as directed  by the Deputy Secretary of Defense in 2007. As a result of DOD’s not fully implementing the 2007 NextGen  memorandum—including developing or revising a DOD directive that  specifies DOD’s objectives with respect to NextGen, issuing an  implementation plan that includes detailed transition planning for ADS-B  and is updated semiannually, and providing recurring progress reports to  the Deputy Secretary of Defense—DOD components have lacked  direction and cohesion while trying to address FAA’s requirement to equip  military aircraft. Both the  Department of Transportation and DOD stated that they would approve  one or more solutions to address ADS-B Out related security risks. Appendix I: Objectives, Scope, and Methodology

Senate Report 114-255, accompanying a bill for the National Defense  Authorization Act of Fiscal Year 2017, included a provision that we  assess issues related to the defense implications of implementation of the  Federal Aviation Administration’s (FAA) Next Generation Air  Transportation System (NextGen) and Automatic Dependent  Surveillance—Broadcast (ADS-B), a main component of NextGen. This  report assesses the extent to which (1) the Department of Defense (DOD)  and the FAA have identified security and operations risks and approved  solutions to address these risks to military aircraft equipped with ADS-B  Out technology; and (2) DOD has implemented key tasks in the 2007  Deputy Secretary of Defense memorandum on implementing NextGen. To assess the extent to which DOD and FAA have identified security and  operations risks and approved solutions to address these risks to military  aircraft equipped with ADS-B Out technology, we reviewed policies,  procedures, guidance, assessments, and other relevant documents from  DOD, FAA, and NORAD that address ADS-B Out implementation,  acquisition, operations, and cybersecurity risk management and  mitigation, and any other issues that might be pertinent to identifying and  addressing operations and security risks resulting from ADS-B Out.
Why GAO Did This Study

DOD has until January 1, 2020, to equip its aircraft with ADS-B Out technology that would provide DOD, FAA, and private citizens the ability to track their flights in real-time and track flight patterns over time. This technology is a component of NextGen, a broader FAA initiative that seeks to modernize the current radar-driven, ground-based air transportation system into a satellite-driven space-based system.
Senate Report 114-255 included a provision for GAO to assess the national defense implications of FAA's implementation of ADS-B. This report assesses the extent to which (1) DOD and FAA have identified operations and security risks and approved solutions to address these risks to ADS-B Out -equipped military aircraft; and (2) DOD has implemented key tasks in the 2007 memorandum on implementing NextGen.
GAO analyzed risks identified by DOD and FAA related to ADS-B vulnerabilities, and how they could affect current and future air defense and air traffic missions. GAO also reviewed the tasks in the 2007 NextGen Memorandum and assessed whether the eight tasks specifically related to ADS-B were implemented.

What GAO Found

Since 2008, the Department of Defense (DOD) and the Department of Transportation's Federal Aviation Administration (FAA) have identified a variety of risks related to Automatic Dependent Surveillance-Broadcast (ADS-B) Out technology that could adversely affect DOD security and missions. However, they have not approved any solutions to address these risks. Compared with other tracking technology, ADS-B Out provides more information, such as an aircraft's precise location, velocity, and airframe dimensions, and better enables real-time and historical flight tracking. Individuals—including adversaries—could track military aircraft equipped with ADS-B Out technology, presenting risks to physical security and operations. This readily available public information allowed GAO to track various kinds of military aircraft. ADS-B Out is also vulnerable to electronic warfare and cyber-attacks. Since FAA is planning to divest radars as part of ADS-B implementation, homeland defense could also be at risk, since the North American Aerospace Defense Command relies on information from FAA radars to monitor air traffic. DOD and FAA have drafted a memorandum of agreement that focuses on equipping aircraft with ADS-B Out but does not address specific security risks. Unless DOD and FAA focus on these risks and approve one or more solutions in a timely manner, they may not have time to plan and execute actions that may be needed before January 1, 2020—when all aircraft are required to be equipped with ADS-B Out technology.
Of the eight tasks associated with the implementation of ADS-B Out technology in the 2007 DOD NextGen memorandum—issued by the Deputy Secretary of Defense to ensure that the NextGen vision for the future national airspace system met DOD's requirements and the appropriate management of DOD's resources—DOD has implemented two, has partially implemented four, and has not implemented two. DOD has established a joint program office and identified a lead service, but it has only partially validated ADS-B Out requirements, developed a directive, issued an implementation plan, and incorporated NextGen into the planning, budgeting, and programming process. DOD has not taken significant action to integrate the needs and requirements of DOD components related to ADS-B into cohesive plans and policies for inclusion in NextGen joint planning and development, and has not provided periodic and recurring NextGen progress reports to the Deputy Secretary of Defense. As a result of DOD not fully implementing the 2007 NextGen memorandum, DOD components have lacked direction and cohesion while trying to address FAA's requirement to equip military aircraft.
This is a public version of a classified report GAO issued in January 2018.

What GAO Recommends

GAO is recommending that DOD and FAA approve one or more solutions to address ADS-B -related security risks; and that DOD implement key tasks to facilitate consistent, long-term planning and implementation of NextGen. DOD and the Department of Transportation generally concurred and described planned actions to implement the recommendations.