At the beginning of June 2015, news accounts indicated that in 67 of 70 covert tests of security checkpoints at U.S. airports, conducted by the Department of Homeland Security’s (DHS) Office of Inspector General, Transportation Security Administration (TSA) officers and equipment failed to detect simulated weapons. The report containing these findings remains classified, but the leak of its results produced an understandable outcry of criticism in the Congress and the news media and a rapid series of responses within DHS and TSA, including the resignation of the acting head of TSA and the announcement by the DHS Secretary of a number of steps designed to improve screening operations, including:

– Training screeners to address the specific detection vulnerabilities revealed by the covert tests;
– Increasing the use of manual screening measures, including the reintroduction of hand-held metal detectors to resolve alarms at the checkpoint;
– Increasing the random use of explosives trace detection equipment;
– Assessing how screening technology equipment (such as Advanced Imaging Technology) can be improved;
– Evaluating, and as necessary revising, TSA’s procedures for expedited screening of passengers; and
– Continuing covert testing of checkpoint security performance, including a same-day debriefing of screeners on what did or did not function effectively along with immediate remedial actions.

The performance of airport checkpoint screening has long been of concern, as reflected in a 2009 report to Congress prepared by the Congressional Research Service.

Screener performance is a continuing concern as covert testing results have repeatedly demonstrated existing weaknesses in screening procedures and capabilities that could potentially be exploited by terrorists or criminals seeking to attack the aviation system. These weaknesses may reflect a combination of policies, procedures, technology capabilities, and screener human performance, although weakness in screener human performance has been emphasized as a particular concern.

It remains to be seen whether the latest efforts by DHS and TSA will remedy the situation.

The focus on the airport checkpoints has a long history, both before and after 9/11, and is understandable given that this is the most visible, heavily funded, and scrutinized of all transportation security measures. At the same time, security officials state that aviation security is premised on the notion of security layers, of which the checkpoint is only one element, wherein if one layer fails another will support or replace it in thwarting an attack.

The principal security layers protecting commercial aviation include airport security, passenger prescreening, checkpoint screening of passengers and carry-on baggage, checked bag screening, and aircraft and onboard security.

Intelligence. Intelligence is considered the first layer of aviation security and has been key in foiling a number of terrorist plots against aviation. A large part of the total intelligence effort within DHS and TSA has been devoted to commercial aviation, including in the development of mechanisms for sharing security information between federal and nonfederal stakeholders in aviation security.

Airport security. Of all the major aviation security layers, airport security is perhaps the least changed since 9/11, with the federal role exercised mainly through establishment of requirements for, and approval and oversight of Airport Security Programs that must be maintained by all commercial U.S. airports, whereas the airport operators themselves are primarily responsible for most security functions.

Passenger Prescreening. Assessing the risk posed by would-be airline passengers before their entry into security checkpoints is a federal responsibility, which is carried out by TSA and DHS’s Customs and Border Protection (CBP) division. These programs, including TSA’s Secure Flight (which seeks to identify high-risk passengers that are to receive extra security attention) and Pre√ (under which individuals who voluntarily submit to a background check process that identifies them as low risks receive expedited screening at security checkpoints) have had some success in improving the prescreening process but have raised certain privacy concerns in doing so.

Checkpoint Passenger and Carry-on Baggage Screening. At the security checkpoints, passengers and their carry-ons are subjected to a variety of techniques aimed at detecting and removing dangerous items, with the goal being (according to TSA) “to strike the appropriate balance between preventing security breaches and maintaining the efficient movement of law-abiding passengers through the security checkpoints.” These techniques include validation of travel documents, use of various types of electronic detection and imaging technologies, behavior recognition and physical searches.

Checked Bag Screening. There are two basic types of checked bag detectors: Explosives detection systems (EDS), which currently serve as the primary screening method and utilize x-rays with computer-assisted imaging to identify suspicious items that may contain explosives; and Explosives Trace Detection (ETD) machines, which help to resolve EDS alarms, or serve as the primary screening method when EDS equipment is not available, by detecting traces of the vapors or residue of explosive material.

Aircraft and Onboard Security. This “last line” of security defenses, for the protection of the aircraft and its crew and passengers on the ground and in flight, includes a variety of measures – many of which were strengthened in the immediate aftermath of 9/11:

– Hardened cockpit doors
– Federal Air Marshals
– Federal Flight Deck Officers Program, under which qualified airline pilots and certain other flight crew members are authorized to have access to firearms for the defense of the aircraft
– Crew member security training.

The large investments in passenger aviation security have produced improvements in virtually all of its security layers, though analyses by the DHS Inspector General, the Government Accountability Office and others have revealed ongoing shortcomings in each. Furthermore, in the absence of successful attacks and with the reassertion of other priorities – including privacy, economic efficiency and overall budgetary constraints – it is not clear that the current level of commercial aviation security will prove sustainable in the long term.

Read more from William about transportation security on SciTech Connect

About the Author:

William Johnstone served on the staff of the National Commission on Terrorist Attacks Upon the United States (9/11 Commission) after working for over 20 years as a Congressional staff member. He is the author of 9/11 and the Future of Transportation Security (2006), Bioterror: Anthrax, Influenza, and the Future of Public Health Security (2008, paperback edition to be published in 2015), and the homeland security section of the annual A Unified Security Budget for the United States (2007-2012). He is the co-author of the monograph “Four Flights and Civil Aviation Security, staff report of the National Commission on Terrorist Attacks Upon the United States” (2004), and a contributor to The 9/11 Commission Report: Final Report of the National Commission on Terrorist Attacks Upon the United States (2004). In his time as a Congressional staff member, Johnstone served as legislative director for U.S. Senators Wyche Fowler, Jr. (D-GA) and Max Cleland (D-GA). Mr. Johnstone grew up in Atlanta, GA and attended Emory University. He currently lives in Rockville, MD with his wife and son, and is a consultant and writer on homeland security matters.

About the Book:

Protecting Transportation: Implementing Security Policies and Programs provides a thorough overview of transportation security in the United States, with a focus on policy. The book coversall major transportation modes and puts the American security system into perspective against other national and international systems.

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