Airport Passenger Screening: Background and Issues for Congress

Congressional research reportApr 23, 2009

Ask Donna

What actually matters in this document.

Text

ȱȱǱȱȱȱ

ȱȱȱ

ȱȱ

ȱȱȱ¢ȱ

ȱŘřǰȱŘŖŖşȱ

ȱȱȱ

ŝȬśŝŖŖȱ

ǯǯȱ

ŚŖśŚřȱ

ȱȱȱ

Prepared for Members and Committees of Congress

ȱȱǱȱȱȱ ȱȱȱ

¢ȱ

Over the next several years, the Transportation Security Administration (TSA) will likely face

continuing challenges to address projected growth in passenger airline travel while maintaining

and improving upon the efficiency and effectiveness of passenger screening operations. New

initiatives to expand the role of TSA personnel beyond screening operations, as well as initiatives

to improve screening efficiency and effectiveness through the deployment of new technologies,

will likely require additional investment. In addition to annual appropriations of $250 million in

FY2008 and FY2009, a portion of the $1 billion identified for aviation security in the stimulus

measure (P.L. 111-5) has been designated for acquiring and deploying technologies to screen

passengers for explosives.

However, policymakers and aviation security planners have not yet agreed upon a well-defined

strategy and plan for evolving airline passenger and baggage screening functions to incorporate

new technologies, capabilities, and procedures to more effectively and efficiently detect potential

threats to aviation security.

Ongoing challenges to maintaining and improving upon screening functions include: addressing

the potential impacts of projected airline passenger traffic growth on screening operations;

optimizing screening efficiency and minimizing passenger wait times; addressing potential airport

space constraints for screening checkpoints and equipment; improving the capability to detect

explosives at passenger checkpoints; optimizing inline explosives detection systems for checked

baggage; developing strategic plans for addressing screening technology and human factors

needs; and defining the funding requirements to implement these strategic plans.

A number of initiatives related to passenger and baggage screening are currently being evaluated

by the TSA. These include tests of new passenger checkpoint layouts and field testing of nextgeneration checkpoint technologies for detecting explosives, including explosives chemical trace

detection devices, whole body imaging systems, and advanced technology (AT) X-ray

capabilities.

ȱȱȱ

ȱȱǱȱȱȱ ȱȱȱ

Policy Issues for Airport Passenger Screening................................................................................ 1

Airline Passenger Traffic Growth ............................................................................................. 2

Screening Efficiency and Passenger Wait Times ...................................................................... 2

Space Constraints at Airports .................................................................................................... 3

Improving Explosives Detection at Passenger Checkpoints ..................................................... 3

Strategic Planning for Addressing Technology and Human Factors Needs .............................. 4

Projected Costs and Funding Issues .......................................................................................... 5

Checkpoint Screening Human Performance.................................................................................... 6

Potential Impacts of Respecting Privacy on Screening Performance.............................................. 7

Covert Testing ................................................................................................................................. 8

Threat Image Projection ................................................................................................................ 12

X-Ray Imagery and Carry-On Baggage Screening Performance.................................................. 13

Passenger Checkpoint Efficiency .................................................................................................. 15

Passenger Wait Times.............................................................................................................. 15

The Link Between Checkpoint Efficiency, Airport Terminal Design and Vulnerability

Reduction ............................................................................................................................. 17

Queuing Practices and Procedures .......................................................................................... 18

The Tailored Self-Select Screening Lane Initiative................................................................. 19

The Registered Traveler Program ........................................................................................... 20

Options for Further Streamlining Passenger Checkpoint Procedures ..................................... 22

Checkpoint Procedures for Liquids......................................................................................... 23

Passenger Education and Informational Materials.................................................................. 25

Checkpoint Evolution and Related Initiatives ............................................................................... 25

Next Generation Checkpoint Technologies ................................................................................... 27

Explosives Trace Detection Technologies............................................................................... 29

Explosives Trace Detection (ETD) Machines................................................................... 29

Bottle and Liquid Explosives Scanners ............................................................................ 29

Walkthrough Explosives Trace Detection Portals............................................................. 30

Whole Body Imaging Technologies ........................................................................................ 30

X-Ray Backscatter Imaging Systems................................................................................ 32

Millimeter Wave Imaging Systems ................................................................................... 33

Advanced Technology X-Ray Equipment............................................................................... 34

Other Candidate Technologies and Applications for Aviation Security Screening ................. 34

Screening Airport Workers ............................................................................................................ 35

Screening and Vetting of Airline Crews ........................................................................................ 37

Figure 1. Average Peak Wait Times at Screening Checkpoints ..................................................... 17

ȱȱȱ

ȱȱǱȱȱȱ ȱȱȱ

Table 1. Emerging Checkpoint Technologies ................................................................................ 28

Author Contact Information .......................................................................................................... 39

ȱȱȱ

ȱȱǱȱȱȱ ȱȱȱ

istorically, airline passenger screening functions have focused on checkpoint screening

using magnetometers to detect metallic weapons on passengers and X-ray systems to

examine carry-on items. These methods have changed little since they were first

implemented at commercial airports in the United States during the early 1970s. Recently,

however, new initiatives to expand the role of TSA personnel beyond traditional physical

screening of passengers and their belongings, as well as initiatives to improve screening

efficiency and effectiveness through the deployment of new technologies, have been implemented

and are being tested. These changes are coming about largely in response to recommendations

and statutory requirements to address threats posed by explosives carried by passengers or in their

carry-on items.

Addressing the identified need to effectively detect explosives on passengers and in carry-on

items will likely require considerable investment and resources. However, policymakers and

aviation security planners have not yet agreed upon a clear strategy and well-defined plan for

evolving airline passenger screening functions to incorporate new technologies, capabilities, and

procedures to more effectively and efficiently detect explosives, weapons, and other threat objects

as well as individuals who may pose a threat to aviation security.

Over the next several years, the TSA will likely face continuing challenges to address projected

growth in passenger airline travel while maintaining and improving upon the efficiency and

effectiveness of passenger and baggage screening operations. Addressing these challenges raises a

number of significant policy issues related to allocating resources and funding passenger

screening initiatives, adequately addressing human performance issues in the design of future

passenger screening systems, and developing effective strategies for deploying next generation

screening technologies.

¢ȱ ȱȱȱȱȱ

The TSA faces a number of ongoing challenges to maintain and improve upon the effectiveness

and efficiency of passenger screening functions. These challenges include:

•

Addressing projected airline passenger traffic growth and its potential impacts on

screening operations;

•

Optimizing screening efficiency and throughput and minimizing passenger wait

times;

•

Identifying and addressing potential airport space constraints for screening

checkpoints and equipment;

•

Improving the capability to detect explosives at passenger checkpoints as

recommended by the 9/11 Commission and called for in legislation;

•

Developing strategic plans for addressing identified technology and human

factors needs related to passenger screening; and

•

Defining funding requirements to implement these strategic plans.

There are numerous policy issues regarding the strategies and approaches for addressing these

ongoing challenges. Some of the key issues are briefly discussed below.

ȱȱȱ

ŗȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱȱȱ ȱ

Currently, across the United States and its territories, passenger screening is conducted at about

450 airports. In total, there are more than 750 screening checkpoints and slightly more than 2,000

screening lanes at the nation’s commercial airports.1 The Federal Aviation Administration (FAA)

projects that domestic passenger traffic will increase at an average annual rate of about 3% from

2010 through 2020 and international passenger traffic will increase at a rate of approximately

4.5% per year.2 Based on these projections, passenger volume at screening checkpoints is

expected to increase by more than 25% over the next eight years, although a prolonged economic

slowdown could moderate the pace of this growth to some degree.

In 2006, the TSA reported that it had screened over 700 million passengers and other individuals

accessing the secured areas of airports in the United States. If airline passenger traffic grows as

predicted, then the TSA will likely be screening over one billion people annually by 2024, or

perhaps sooner if initiatives to conduct random and targeted screening of airport employees,

currently being conducted under trial programs at selected airports, are expanded across the entire

aviation system. Significant resources will likely be needed to address future screening needs to

accommodate this growth without causing an operational impact on screening efficiency and

effectiveness.

ȱ¢ȱȱȱȱȱ

With respect to screening efficiency, the TSA has set an objective of keeping average passenger

wait times to ten minutes or less ever since its inception in 2002. While the average wait times

aggregated across the entire aviation system have generally met this objective, wait times at

larger airports, particularly the busiest airports, often exceed ten minutes.3 Passengers frequently

experience long waits in screening checkpoint queues, particularly during peak periods at the

nation’s busiest airports.

At many larger airports, space constraints and other design considerations have limited the TSA’s

ability to add additional screening lanes and reconfigure checkpoints to improve the flow of

passengers. This has resulted in lengthy wait times during peak periods, sometimes exceeding 40

minutes, at many of the nation’s largest airports.

Wait times are not just a problem at large airports, as smaller regional airports may also face

challenges with large seasonal fluctuations in passenger volume coupled with screening lane and

workforce constraints that may limit the ability to respond to spikes in passenger traffic.

Therefore, in addition to accommodating projected future growth in passenger volumes, the TSA

faces ongoing challenges at various airports to improve upon the overall efficiency of passenger

screening operations and meet stated wait time objectives without sacrificing performance.

United States Government Accountability Office. Aviation Security: TSA’s Staffing Allocation Model Is Useful for

Allocating Staff among Airports, but Its Assumptions Should Be Systematically Reassessed, GAO-07-299 (February

2007).

Federal Aviation Administration, FAA Aerospace Forecast: Fiscal Years 2009-2025.

United States Government Accountability Office. Aviation Security: TSA’s Staffing Allocation Model.

ȱȱȱ

Řȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱȱȱȱ

Space constraints within airports are likely to become an increasing concern for the TSA as it

seeks to increase the number of screening lanes to meet projected growth in the number of airline

passengers. These constraints are also likely to become an increasingly important issue as the

TSA is seeking to reconfigure checkpoints over the next several years to accommodate new

screening technologies. The TSA is also seeking to expand the footprint of the screening

checkpoint queue and screening lanes to provide a more relaxed atmosphere for travelers and

provide behavioral detection officers (BDOs) with additional space to mingle and interact with

passengers in an effort to improve the detection of suspicious behavior and possible hostile intent.

These factors may combine to result in a considerably larger footprint for screening checkpoints

compared to current configurations, particularly at older airports constructed when passenger

volume was considerably less and the footprint of screening checkpoints was quite small.

Optimizing the layout of screening checkpoints at these airports may require a considerable

investment in redesigning and expanding airport facilities to accommodate proposed future

changes to screening checkpoints that are intended to optimize efficiency and performance across

the entire network of commercial airports.4 Particular challenges may be encountered at smaller

regional airports that have limited capability and access to resources to expand, as well as at large

airports with older terminals that were not initially designed with these new security challenges in

mind.

ȱ¡ȱȱȱȱȱ

The 9/11 Commission recommended that the TSA give priority attention to implementing

technology and procedures for screening passengers for explosives, something not currently done

routinely at screening checkpoints. Provisions to improve checkpoint technologies to detect

explosives were included in the Intelligence Reform and Terrorism Prevention Act of 2004 (P.L.

108-458, hereafter the “Terrorism Prevention Act”).

To address the issue of detecting explosives carried by passengers, the TSA tested walk-through

trace detection portals, known as explosives trace portals (ETPs), and has implemented

procedures for conducting pat-down searches of passengers for explosives. Full deployment of

the walk-through trace detection portals, or puffer machines, for use in secondary screening of

selected passengers had been part of the TSA’s strategy for screening passengers for explosives,

but this initiative has been put on hold due to maintenance issues with deployed systems. The

effectiveness of the strategy has also been brought into question by the foiled plot to bomb U.S.bound airliners using liquid explosives uncovered in August 2006. The TSA is working to identify

strategies and technologies that more completely address the explosives threat posed by

passengers and carry-on items.

In addition to keeping up with increased volumes of people passing through airport screening

checkpoints and improving upon screening efficiency, the TSA faces significant challenges in

The term “optimize” is used extensively throughout this report. The term is broadly defined as improving or

developing as far as possible some measurable aspect of system performance or efficiency through the application of

new technologies, policies, procedures, and systems engineering principles. It should be noted, however, that there are

often inherent tradeoffs among certain measurable aspects of a system’s performance. For example, given current

technological capabilities, there are often tradeoffs between system efficiency and system detection capability.

ȱȱȱ

řȱ

ȱȱǱȱȱȱ ȱȱȱ

addressing 9/11 Commission recommendations and statutory mandates to improve the ability to

detect explosives and bomb-making components carried on passengers and in carry-on items.

There are lingering concerns that, without a significant investment to improve the detection of

concealed explosives and non-metallic weapons at passenger checkpoints, considerable

vulnerabilities will persist. The TSA is pursuing a wide variety of technologies to address the

challenge of detecting explosives at passenger screening checkpoints. These technologies include

walkthrough explosive trace detection portals, whole body imaging (WBI) systems, bottle liquid

scanners, cast and prosthesis scanners, shoe scanners, advanced technology (AT) X-ray systems,

and explosives detection systems (EDS) tailored for carry-on screening applications. These

various technologies will complement, and in some cases replace, existing checkpoint tools such

as magnetometers, hand wands, and explosives trace detection (ETD) equipment.

Under the TSA’s current budget plans, in the near term, deployment of this technology will be

concentrated at the nation’s largest airports and will often be limited to use on those passengers

selected for secondary screening or to resolve alarms set off during primary screening. Full scale

deployment of technologies to screen all passengers and carry-on items for explosives and other

concealed items will involve a considerably larger investment over the long term. However, a

specific long term investment and technology deployment strategy has not yet been agreed upon.

While these various technologies have reached a level of maturity where they can be

operationally deployed, achieving an end state in which all passengers are screened unobtrusively

to detect a broad range of threat objects raises a number of policy issues related to the privacy of

passengers as well as a long term investment strategy for implementing future checkpoint

concepts.

ȱȱȱȱ¢ȱȱ ȱȱ

The challenges to improving screening capabilities stem from the 9/11 Commission’s

recommendations to improve the detection of explosives on passengers and address human

factors considerations related to screener performance.5 Four years after these recommendations

were issued, the Government Accountability Office (GAO) reported that only limited progress

had been made in fielding explosives detection technologies at passenger checkpoints, and the

TSA lacks a strategic plan for the acquisition and deployment of screening technologies.6

Moreover, covert testing at passenger checkpoints continues to provide evidence that, despite the

considerable federal spending on airline passenger screening since the 9/11 terrorist attacks, the

system remains vulnerable, particularly to the threat posed by adversaries attempting to sneak

improvised explosive devices (IEDs) or components to assemble such devices through security

checkpoints and onboard passenger airliners. These vulnerabilities reflect the lack of adequate

technologies deployed at checkpoints capable of detecting explosives materials, as well as

limitations in screener performance that is influenced by a variety of human performance factors.

National Commission on Terrorist Attacks Upon the United States. The 9/11 Commission Report, Washington, DC:

July, 2004.

U.S. Government Accountability Office, Transportation Security Administration Has Strengthened Planning to Guide

Investments in Key Aviation and Surface Transportation Security Programs, but More Work Remains, Statement of

Cathleen A. Berrick, Director, Homeland Security and Justice Issues, Before the Committee on Commerce, Science,

and Transportation, U.S. Senate, May 13, 2008, GAO-08-487T.

ȱȱȱ

Śȱ

ȱȱǱȱȱȱ ȱȱȱ

Provisions in P.L. 110-53 (see section 1607) required the TSA to finalize a strategic plan for

checkpoint explosives detection required by the Terrorism Prevention Act, and fully implement

the plan within one year of enactment. The act also contained provisions (see section 1612) that

eliminate the cap on the system-wide number of TSA screeners, and require specialized training

for screeners on security skills such as behavioral observation and analysis, explosives detection,

and document examination. The act directed the TSA to hire sufficient personnel to ensure

adequate aviation security and reduce average security-related delays to less than 10 minutes. The

act also created a separate “Checkpoint Security Screening Fund,” specifying that $250 million of

the security fees collected during FY2008 were to be deposited into this fund (see section 1601),

and made available for research, development, deployment, and installation of equipment to

improve the detection of explosives at passenger checkpoints. The act also directed the TSA to

carry out a pilot study to examine technologies to improve the security at access control doors and

exit lanes for airport secured areas (see section 1613).

ȱȱȱȱ ȱ

The Implementing Recommendations of the 9/11 Commission Act (P.L. 110-53) included a

provision establishing an Airport Checkpoint Screening Fund. The fund provided $250 million in

passenger security fees for the acquisition and deployment of technologies to improve the

detection of explosives at passenger screening checkpoints in FY2008. The FY2009 Department

of Homeland Security Appropriations Act (P.L. 110-329) provides $250 million for Checkpoint

Support, thus maintaining funding for checkpoint technologies, supplies, and equipment at the

level provided under the Airport Checkpoint Screening Fund in FY2008.

In addition to these appropriations, the American Recovery and Reinvestment Act of 2009 (P.L.

111-5) specifies an additional $1 billion for aviation security, designated for the procurement and

installation of checkpoint explosives detection equipment and checked baggage explosives

detection systems. This additional funding is expected to accelerate the deployment of checkpoint

explosives detection technologies over the next two years. Conference report language (see

H.Rept. 111-16) specifies that projects should be prioritized based on security risks.

Deploying new technologies and reconfiguring screening lanes to incorporate these technologies

and optimize performance and efficiency will likely cost more than $500,000 per screening lane

based on TSA average unit costs for candidate technologies.7 This cost only considers the direct

costs for screening lane technology acquisition and installation, and does not include any costs

associated with expanding or reconfiguring airport terminals to accommodate new checkpoint

designs. Given that there are more than 2,000 screening lanes in operation throughout the United

States, the total cost to upgrade screening checkpoints is likely to exceed one billion dollars in

equipment costs alone.

Additionally, the costs to operate and maintain this screening equipment is likely to cost tens of

thousands of dollars each year per screening lane. Based on these rough estimates, it is apparent

that current funding levels for Checkpoint Support will not support a full-scale, near-term

deployment of emerging passenger checkpoint technologies. Congress may consider various

funding options to expand or accelerate the deployment of these checkpoint technologies. If such

CRS estimates based on unit costs provided in DHS TSA FY2009 congressional budget justification documents.

ȱȱȱ

śȱ

ȱȱǱȱȱȱ ȱȱȱ

options are not pursued, it will likely take ten years or more to achieve full system-wide

deployment.

At present, the TSA has adopted a strategy of focusing its efforts to deploy new checkpoint

screening technologies on larger airports. However, since the aviation screening system in the

United States operates using a single gateway concept, meaning that passengers are only screened

once at their originating airport, focusing investments solely on larger airports could result in

persisting vulnerabilities at smaller regional airports. These vulnerabilities may further persist

without a strategy and commitment to future funding for system-wide deployment of advanced

technology systems for detecting explosives and nonmetallic threat items at checkpoints.

ȱȱ ȱȱ

The aviation security system is a human system involving extensive reliance on human

perception, performance, decision making, and judgment. This is particularly true with regard to

checkpoint screening functions where passenger and carry-on screening involve human resource

intensive activities to detect and resolve potential threat items. An underlying challenge related to

proposed checkpoint expansion and enhancements is addressing ongoing human performance

concerns to improve the detection of dangerous items at checkpoints and incorporate human

factors considerations in the design and operator training for next generation checkpoint

technologies and procedures.

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 which can be affected by various factors. A wide range of human factors

considerations pertaining to screening procedures, training, fatigue and alertness, human

perception and detection capabilities, and judgment and decision making can have a significant

effect on the overall effectiveness of passenger checkpoint screening as well as baggage screening

operations.

Passenger checkpoint screening activities at all passenger airports are carried out by about 30,000

screeners who make up about 60-65% of the total TSA screener workforce. The humans that

operate the system, particularly the screening workforce, have long been regarded as a potentially

highly fallible and vulnerable element of the aviation screening system. This should not be

construed as a reflection on the dedication and commitment of individual screeners to performing

this critical job function. Rather it reflects a combination of the complex challenges faced by

screeners, limitations in human perception and performance, resourceful adversaries who may

employ artful concealment methods, and competing job pressures to accurately detect threat

objects while maintaining an efficient flow of passengers through security checkpoints.

Adversaries seeking to carry out hijackings or bombings by carrying explosive devices, bomb

making components, or handheld weapons through screening checkpoints may attempt to exploit

various limitations on human perception and performance that may compromise security. A

variety of factors may contribute to these human performance limitations, including inadequate

training, lack of motivation and job satisfaction, fatigue, and workplace conditions, as well as

general human perception and performance limitations.

ȱȱȱ

Ŝȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱ ȱȱȱ¢ȱȱ

ȱȱ

Balancing individuals’ rights and expectations of privacy with screening effectiveness is a human

performance challenge. Criminals and terrorists have been known to conceal items in private

areas of the body, especially in the small of the back above the buttocks and high on the thigh.

Screeners are to carefully inspect these areas during pat downs to adequately check for dangerous

items. Also, underwire bras can set off magnetometers, and bras have been used to conceal

dangerous items. One of the most intrusive and most controversial aspects of secondary screening

is the use of pat-down inspections to check selected passengers or to resolve magnetometer

alarms. Specific complaints over pat-down techniques have centered on allegations of

inappropriate touching and unprofessional or rude conduct by screeners. More general complaints

have focused on privacy concerns and perceptions that the pat-down procedures were intrusive

and humiliating.8

A 2005, DHS OIG investigation and audit of pat-down screening procedures found that the TSA

adequately advised passengers of their rights under the pat-down procedures, and appropriately

accommodated those rights.9 The DHS OIG also found that TSA screeners were adequately

trained in pat down inspection procedures and, based on TSA records, additional screening

procedures were performed on proportionate numbers of male and female passengers. Finally, the

DHS OIG found that the TSA had implemented procedures to investigate and resolve passenger

complaints regarding the screening process.

The TSA maintains a screening Performance Management Information System (PMIS) where

recorded complaints are logged. Operations research analysis teams and federal security directors

review complaints logged in the database to track trends and identify areas of concern and take

appropriate actions, including possible disciplinary actions, to resolve specific issues. Complaints

involving allegations of discrimination based on color, race, gender, religion, or national or ethnic

origin are forwarded to the TSA’s Office of Civil Rights for further investigation. Despite

considerable concern raised by some regarding inappropriate behavior during pat-down screening

procedures, the DHS OIG found no systematic problems with the technique.

Nonetheless, privacy groups, such as the American Civil Liberties Union (ALCU), continue to

express concern over potential intrusion on individual rights and alleged cases of sexual

harassment and abuse of passengers, particularly female passengers, by TSA screeners.10 These

concerns, however, raise a significant challenge for the TSA: to maintain high levels of security,

which necessitate resolving all alarms and screening in detail those passengers ascertained to pose

an elevated security risk, while maintaining the privacy rights and dignity of passengers identified

for these secondary screening measures. The principal option under consideration for addressing

these concerns is the use of whole body imaging technologies, discussed below. While these

technologies offer a potential alternative to pat-down screening techniques, they too, raise privacy

concerns because the images generated by these systems can reveal private areas, physical

Department of Homeland Security, Office of Inspector General, Review and Audit of the Transportation Security

Administration’s Use of Pat-Downs in Screening Procedures (REDACTED), November 2005, OIG-06-10.

Ibid.

American Civil Liberties Union, TSA Pat-down Search Abuse, December 21, 2004, New York, NY.

ȱȱȱ

ŝȱ

ȱȱǱȱȱȱ ȱȱȱ

characteristics that individuals may wish to keep private, as well as prosthetics and other assistive

medical devices.

In the fast-paced environment of the passenger checkpoint, pat-down searches may be rushed and

certain areas may be overlooked. The difficulty in detecting threat items on passengers is

compounded by the requirements to respect the privacy of individuals discussed above, as well as

social and cultural norms and individual differences regarding interpersonal contact and

expectations of privacy and modesty. Some have also noted cultural sensitivities toward

handicapped and disabled individuals and point out that screeners are sometimes hesitant to

perform intrusive searches, particularly on individuals wearing various prosthetics.11 Terrorists

and criminals can and have exploited these aspects of individual privacy by concealing prohibited

items in body cavities and near private areas of their bodies, and could also exploit a screener’s

reluctance to perform thorough searches of prosthetic devices. Covert testers also use these

methods to conceal simulated threat items in an effort to test screeners’ abilities to detect items

under real-world conditions and identify vulnerabilities in checkpoint screening that can

potentially be reduced through procedural modifications and/or changes to screener training.

These covert tests have revealed weaknesses in screener performance to detect weapons,

simulated explosives, and components of explosive devices.

ȱȱ

Much of the concern over the performance of airport screening operations has arisen from

information that has been made public regarding the results of covert testing operations. Covert

testing using rudimentary mock bombs and guns started soon after screening checkpoints were

first established in the early 1970s. Following the bombing of Pan Am flight 103 in December

1988, the FAA began more sophisticated “red team” tests to identify weaknesses in screening

performance and other aspects of aviation security. The term red team harkens back to the Cold

War era military exercises where red teams – so designated in reference to the Soviet Union’s red

flag and the association of red with communist groups – adopted strategies and tactics of an

enemy force in simulations and war games.

The use of aviation security red team testing was suspended for a period of time following the

9/11 attacks, largely over concerns that red team practices could potentially put testers in danger

or cause significant panic among passengers because of the acute focus on aviation security and

the lingering public fear following the attacks. In 2003, the TSA’s Office of Internal Affairs and

Program Review (OIAPR) resumed covert testing of passenger screening checkpoints, checked

baggage screening operations, and airport access control measures. At present, this function falls

under the responsibility of the TSA’s Office of Investigations (TSA-OI). In addition to nationwide

covert testing conducted by the TSA-OI, Federal Security Directors (FSDs) at each airport are to

perform local covert testing. The local testing was initially called the Screener Training Exercises

and Assessments (STEA), but is now known as the Aviation Screening Assessment Program

(ASAP) and has been revamped to better reflect the types of threat objects that may be used by

terrorists based on the latest intelligence and threat information.

Jeanne Meserve and Mike M. Ahlers. “TSA Tester Slips Mock Bomb Past Airport Security.” Cable News Network

(CNN), January 28, 2008.

ȱȱȱ

Şȱ

ȱȱǱȱȱȱ ȱȱȱ

While specific performance metrics for covert testing are considered security sensitive, various

media reports of test results suggest that failure rates are often quite high, particularly with

respect to screeners missing simulated improvised explosive devices and explosive components.

For example, it has been reported that during tests conducted in 2006, TSA screeners missed fake

bombs 75% of the time at Los Angeles International Airport (LAX), and 60% of the time at

Chicago O’Hare Airport (ORD).12 The TSA contends that the results, on the surface, appear

discouraging, but are a reflection of highly sophisticated concealment methods being used by

testers to uncover specific system vulnerabilities so that corrective action can be taken.

According to the TSA “... as security officers adapt and begin to consistently discover covert

testing methods, testers start all over again, creating more difficult and harder-to-detect tests. This

years’ long game of cat and mouse more closely simulates real terrorist probing and operations

and keeps officers alert and informed of the latest techniques and improvements.”13 The TSA

points out that this type of testing is fundamentally different from the static, unchanging

performance evaluations that were employed prior to the 9/11 attacks. Since the present day test

protocols are constantly changing, the TSA has primarily used them to provide a snapshot of

specific vulnerabilities in the system. It has not systematically assessed whether screener

performance is improving or getting worse over time, although it asserts that improvements have

been made. According to the TSA, the covert testing methods are primarily used as a tool for

assessing and identifying areas where performance improvements are needed and are potentially

achievable through additional training, operational emphasis, or procedural redesign.

The TSA plans to complete more than 2,500 covert tests of passenger screening checkpoints

annually during FY2008 and FY2009 in an effort to continually identify vulnerabilities and take

corrective action to improve checkpoint screening based on the latest intelligence and information

regarding terrorist weapons and explosives that pose a threat to commercial aviation and methods

for concealing these threat objects.14 While specific test results are considered security sensitive

information, it has been reported that current failure rates are comparable to those observed in

1987 when screeners failed to detect about 20 percent of concealed items during on-the-job

performance testing.15 However, the TSA asserts that the testing methods used at that time was in

no way comparable to current covert testing methods.

Concerns over advance warning given prior to covert testing and screener performance

evaluations has been a longstanding issue. While media reports have suggested that some recent

TSA covert tests were leaked to screeners, the TSA maintains that its procedures are designed to

minimize the likelihood that screeners will be tipped off regarding a covert test operation, while

providing appropriate notification to TSA airport level management and local law enforcement to

ensure that the tests are conducted safely. Nonetheless, cases of screeners being tipped off

regarding covert testing have been documented. For example, in 2004, the DHS IG found that

screeners at the Jackson-Evers International Airport in Mississippi had been given information

regarding upcoming covert tests, including details about the gender and race of the testers, the

type of test items being used, and the location of test items on the tester and in carry-on and

Ibid.

Transportation Security Administration, Covert Testing: Why is Covert Testing Important?

Transportation Security Administration, Fiscal Year 2009 Congressional Justification, Transportation Security

Support.

Sara Kehaulani Goo. “Airport Screeners Do Poorly, Panel Told.” The Washington Post, April 23, 2004, p. A8.

ȱȱȱ

şȱ

ȱȱǱȱȱȱ ȱȱȱ

checked baggage.16 Also, it was revealed that in April 2006, TSA headquarters staff used an

internal electronic communications system to provide field level personnel with heads up

information regarding possible covert testing operations, providing details regarding testing

methods.17 The TSA responded that it was investigating the allegations, but preliminary findings

indicated that the internal communication regarding the testing was considered suspicious by a

headquarters official who decided to forward it to federal security directors at airports across the

country, but the email was recalled 13 minutes after it was sent. Based on these findings, the TSA

concluded that the dissemination of information regarding the upcoming covert test did not

appear to be a deliberate attempt to tip off screeners or screening supervisors. Former TSA

Administrator Kip Hawley testified that there was nothing to indicate that anyone within the TSA

attempted to tip off airport security screeners regarding covert testing in this incident.18

In addition to concerns over possible advance warning of covert tests, concerns have also been

raised that the TSA does not have adequate processes in place to systematically document causes

of covert testing failures and carry out appropriate remedial action. A GAO audit of TSA’s covert

testing programs, including covert testing of passenger screening, baggage screening, and airport

access control systems, found that the TSA-OI has failed to systematically record, document, and

inform management of causes for test failures as would be expected if federal government

standards for internal control were fully implemented.19 The GAO further noted that the TSA

lacks a systematic process to ensure that recommendations by TSA-OI are fully considered, and

management decisions for adopting or rejecting these recommendations are appropriately

documented.

While the TSA-OI made numerous recommendations to the TSA’s Office of Security Operations

during the period reviewed (March 2003-June 2007), the GAO found that often, in more than

40% (18 out of 43) of cases, TSA management either took no action or it was unclear how the

action taken addressed the recommendation. The lack of a formal process made it difficult to

assess how the recommendations related to covert testing results, and in turn, how actions taken

remedied problems identified by the TSA-OI. The GAO concluded that without such a process,

the TSA’s ability to strengthen aviation security based on the findings and recommendations of

covert testers is limited, and it recommended that the TSA establish a system for documenting the

results and recommendations stemming from covert testing and to track actions taken in response

to these recommendations.

In addition to the internal covert testing by the TSA’s Office of Inspections, both the Department

of Homeland Security Office of Inspector General and the GAO independently conduct periodic

audits and inspections of TSA screening functions that often include covert testing methods.

While many of the details of these audits are considered security sensitive, the results of these

tests have provided Congress and observers with important insights regarding the persisting

vulnerabilities at airport passenger screening checkpoints.

Department of Homeland Security, Office of Inspector General. Letter Report: TSA’s Management of Aviation

Security Activities at the Jackson-Evers International Airport, August 2007, OIG-07-73.

Honorable Bennie G. Thompson, Chairman, Homeland Security Committee, U.S. House of Representatives, “Cover

Blown: Did TSA Tip Off Airport Screeners about Covert Testing.” Statement Released November 14, 2007.

“TSA: Airport Screeners Weren’t Tipped Off,” Air Safety Week, November 19, 2007.

United States Government Accountability Office. Transportation Security: TSA Has Developed a Risk-Based Covert

Testing Program, but Could Better Mitigate Aviation Security Vulnerabilities Identified Through Covert Tests,August

2008, GAO-08-958.

ȱȱȱ

ŗŖȱ

ȱȱǱȱȱȱ ȱȱȱ

Most notably, in a series of covert tests conducted in 2007, GAO investigators demonstrated that,

even when proper procedures were followed, checkpoint screening often failed to detect

concealed explosives and components that could be used to construct an explosive device

potentially capable of downing an airliner.20 For these tests, the investigators constructed two

improvised devices: an improvised explosive device (IED), consisting of a liquid explosive that

would be triggered by a low-yield detonator (i.e., a blasting cap); and an improvised incendiary

device (IID), constructed from commonly available products including a liquid component. The

investigators obtained the materials to construct these devices at local stores and over the Internet,

spending less that $150. The investigators then employed various methods to conceal these items

on their persons and in carry-on baggage, demonstrating that it is possible to pass either a

constructed device or the components to build an IED or an IID through airport screening

checkpoints without detection. In all cases, screeners failed to detect or prohibit the carriage of

IED and IID components, including liquid components.

The GAO noted that the specific security weaknesses exploited in these covert tests, which were

not divulged for security reasons, were identified by reviewing publicly available information,

including information often shared through the Internet and readily available to terrorist groups.

By exploiting these weaknesses, the investigators were able to pass these components, including

banned liquid items, through various security checkpoints. While the investigators were subjected

to secondary screening for unrelated reasons in some instances, pat-down searches and other

secondary screening methods failed to detect the improvised explosives or prohibited items. In

other instances, screeners challenged the investigators for failing to fully comply with various

procedures, including procedures regarding permissible quantities and packaging of liquids.

The GAO concluded that its “tests clearly demonstrate that a terrorist group, using publicly

available information and few resources, could cause severe damage to an airplane and threaten

the safety of passengers by bringing prohibited IED and IID components through security

checkpoints.”21 In reviewing these results, the TSA has acknowledged checkpoint vulnerabilities

related to human performance, screening procedures, and checkpoint technologies. The GAO

asserted that improvements in these areas may further reduce the risks to commercial aviation

posed by IEDs and IIDs.

While the GAO’s specific recommendations focusing on ways to improve screener detection of

threat objects made to the TSA were not publicly divulged, the GAO also urged the TSA to take

the following actions to enhance checkpoint screening operations:

•

Establish dedicated airport screening lanes to handle those passengers posing an

elevated risk and for those passengers with special needs;

•

Introduce more aggressive, visible, and unpredictable checkpoint procedures,

such as random pat-down and hand-wand screening; and

•

Continue to develop new technology at checkpoints to better detect concealed

items.

United States Government Accountability Office. Statement of Gregory D. Kutz, Managing Director, Forensic

Audits and Special Investigations, and John W. Cooney, Assistant Director, Forensic Audits and Special Investigations.

Aviation Security: Vulnerabilities Exposed Through Covert Testing of TSA’s Passenger Screening Process. Testimony

Before the Committee on Oversight and Government Reform, House of Representatives, November 15, 2007.

Ibid., p. 10.

ȱȱȱ

ŗŗȱ

ȱȱǱȱȱȱ ȱȱȱ

These recommendations for action reflect a continuing concern that, despite considerable

investment in checkpoint screening technologies and personnel since the terrorist attacks of

September 11, 2001, significant vulnerabilities persist in checkpoint screening operations. In

testimony before the House Committee on Homeland Security on November 14, 2007, former

DHS Inspector General Clark Kent Ervin stated that “[t]he sad fact is that for all the dollars and

attention that has been focused on screener performance since 9/11, study after study ... shows

that it is just as easy today to sneak these deadly weapons past screeners [as] it was on 9/11.”22

While Ervin’s conclusions have been somewhat controversial and widely disputed by the DHS

and the TSA, his general recommendations parallel various initiatives put forward by Congress

and the Bush Administration to improve screener performance. Specifically, Ervin recommended

extensive training and frequent retraining of screeners under simulated real-world conditions;

remedial action for screeners and supervisors that fail performance tests and termination of those

employees that habitually perform on a sub-par level; and systemwide deployment of next

generation screening technologies, such as whole body imaging and advanced X-ray systems.

These recommendations reflect specific needs for improvements in human factors and training for

screening personnel as well as investment in screening technologies. The TSA is actively

pursuing an approach to address checkpoint screening technology and human factors through its

recently launched checkpoint evolution initiative.

ȱ ȱȱ

In addition to covert testing, which tests screener performance in detecting concealed threat items

on passengers and in carry-on items under operational conditions, the performance of screeners

that inspect X-ray images of carry-on items is routinely monitored and evaluated using a

technology called Threat Image Projection (TIP). This technology provides the capability to

overlay virtual, computer-generated, threat objects over X-ray images of passenger’s screened

property during normal screening operations or to present virtual images of baggage containing

concealed threat items. TIP was first fielded by the FAA in 1999.

Following the terrorist attacks of September 11, 2001, TIP was discontinued as an operational

performance tool over concerns that screener responses to TIP images would increase delays

amidst the heightened focus on aviation security threats. However, viewing the technique as a

valuable operational testing and performance tool, the TSA reintroduced TIP in 2003 using a

greatly expanded database of threat images said to be more representative of weapons and

concealment tactics that may be used by terrorists. In comparison to the FAA TIP system prior to

the 9/11 attacks which had about 200 images in its database, the TIP system in use by the TSA

today has over 2,000 images,23 with new images constantly being added based on identified

threats and concealment methods identified through intelligence and field operations. Fielded Xray equipment in use at screening checkpoints is TIP-ready. That is, these machines are designed

to store and display TIP database images, and are therefore referred to as TIP-Ready X-ray or

TRX equipment. These systems are networked, and linked into TSA laboratories that create and

distribute new TIP imagery periodically based on intelligence regarding new threat items and

concealment methods.

Statement of Clark Kent Ervin Before the Committee on Homeland Security, House of Representatives, Cover

Blown: Did TSA Tip Off Airport Screeners About Covert Testing?, November 14, 2007.

Transportation Security Administration, Aviation Security System of Systems: THEN and NOW.

ȱȱȱ

ŗŘȱ

ȱȱǱȱȱȱ ȱȱȱ

On TRX equipment, images of weapons and explosives are projected on the X-ray images of

actual bags being screened. This is done for several purposes. First, by providing periodic threat

images to the screeners, the system promotes alertness and acts as a mitigation for boredom and

complacency, two factors that can have a significant negative impact on human performance.

Second, the ability to collect data regarding screening performance and screener sensitivity in

real-world settings serves as an invaluable tool for human factors researchers studying screener

performance. For example, these researchers can look at performance as a function of time of day

and time on shift, to optimize the scheduling of shifts and breaks for screeners. Researchers can

also use the TIP data to identify particular threat items or methods of concealment that are often

missed, and in response can tailor recurrent screener training and re-qualification to emphasize

and correct specific weaknesses, either on a systemwide, an airport-by-airport, or even on an

individual screener level. Third, TIP provides a quantifiable means to evaluate the performance of

screeners at individual, work group, airport, or systemwide levels of analysis. As such, it can be

used to track progress over time and can be used to document deficient levels of individual

performance that establish grounds for dismissal. TIP has been one of the most significant

technology changes to carry-on screening since X-ray screening techniques were first

implemented in the early 1970s, and directly addresses human performance aspects of checkpoint

screening functions.

However, TIP is limited in its scope and provides data on only one aspect of screening operations:

screener preliminary threat identification of X-ray images. TIP does not provide data on whether

proper procedures were carried out once a threat object was suspected and flagged by the X-ray

screener, whether explosive trace detection (ETD) systems were properly used to conduct

secondary evaluations of suspected explosives, and so on. Also, TIP does not provide any data on

the screening of passengers themselves or their checked baggage; it only provides data on the

screening of carry-on baggage. Nonetheless, TIP is widely regarded as an important screener

evaluation tool, and it will likely remain an integral part of advanced technology (AT) X-ray

equipment deployment in the future.

Ȭ¢ȱ ¢ȱȱ¢Ȭȱȱȱ

Current generation X-ray systems provide significantly higher resolution than systems that were

deployed at airports in the 1990s and prior. However, these systems only provide a single view

angle, typically an overhead view, of screened items. Nonetheless, in addition to increased image

resolution, image coloration and other image enhancement features allow screeners to more easily

differentiate organic and metallic materials and provide the capability to use color contrast to

better differentiate certain elements of the X-ray image. For example, the coloration allows

organic materials to stand out from inorganic materials making it easier to detect dense organic

matter that may be indicative of an IED, and provides differential coloration of metals to allow

for easier detection of metallic weapons.

In addition to selective coloration, newer X-ray systems allow for a wide array of image

enhancement functions to highlight or turn off and declutter certain features in a process known

as image “stripping.” However, some research has shown that individual image enhancements do

not necessarily improve IED detection compared to viewing of the original X-ray image,

ȱȱȱ

ŗřȱ

ȱȱǱȱȱȱ ȱȱȱ

suggesting that the greatest advantage derived from current single-view X-ray systems may be

their improved image resolution.24 Nonetheless, viewing multiple image enhancements in

combination – such as stripping out organic items or metallic items, or displaying a negative

image – can potentially help resolve image ambiguities and possibly improve detection. While

currently deployed X-ray systems have these capabilities, time pressures at busy screening

checkpoints may often preclude detailed examination using various combinations of these image

enhancement capabilities.

Object orientation in the X-ray view is often a key determinant to whether an object will be

recognized or detected. Prohibited items, such as guns and knives, presented at odd viewing

angles can often be missed, even by highly trained screeners. At present, the main tool to address

detection performance of objects presented at difficult-to-recognize view angles is through the

use of computer-based training using TIP imagery of threat items presented at various view

angles. Since threat object recognition and detection is a skill that is likely to continually improve

with experience and exposure to both TIP imagery and artfully concealed real-world threat items,

retention of high-performing experienced X-ray screeners is likely to remain a key component of

maintaining high levels of screening performance.

Research has also shown that pre-employment screening to assess aptitude for interpreting X-ray

images, recognizing objects and detecting prohibited items can substantially increase X-ray

screening performance.25 Thus, with regard to establishing and maintaining effective X-ray image

screening performance, it appears that a specific emphasis should be placed on screener selection

and training, as well as initiatives to retain high-performing X-ray image screening personnel.

Besides improvements in screener selection and training in methods of performing pat-down

searches and interpreting X-ray images, addressing additional human factors issues related to the

screener work setting – including fatigue, motivational factors, and environmental considerations,

such as lighting, noise, and operations tempo – may also yield improvements in the ability to

detect threat items and individuals with hostile intent.

With regard to advancements in screening technology, next generation advanced technology (AT)

X-ray systems are capable of providing multiple image views, usually two views that provide

both a overhead view and a profile view of the X-rayed item. Some of these systems also

incorporate computer image interpretation algorithms that automatically search for, and either

highlight or alert the operator to, suspected threat items such as explosives and weapons. These

features, however, can often be viewed negatively by operators and can slow the screening

process if they generate high numbers of false alarms or false positives. The specific performance

characteristics of AT X-ray systems being acquired and deployed by the TSA, including

information about their false alarm rates, is not publicly available, but remain important

considerations in the selection of systems and system features for operational deployment. Policy

considerations regarding the acquisition and deployment of AT X-ray systems are further

discussed in the section on “Next Generation Checkpoint Technologies.”

Adrian Schwaninger, “X-ray Imagery: Enhancing the Value of the Pixels,” Aviation Security International, October

2005, pp. 16-21.

Ibid.

ȱȱȱ

ŗŚȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱȱ¢ȱ

While the ability to detect threats is the primary metric for evaluating passenger checkpoint

system performance, maintaining checkpoint efficiency has also been given a high priority.

However, the well documented phenomenon of speed-accuracy trade-offs in human performance

highlight the fact that increasing system throughput can lead to missed threats and a deterioration

of system effectiveness. Therefore, policymakers and aviation security strategists have generally

focused on striking a balance between maintaining reasonable wait times and high levels of threat

detection. While research and engineering has focused on optimizing screening lane efficiency

and effectiveness, longstanding wait time objectives have been set by policy, largely based on

what is regarded as reasonable to expect by the traveling public.

ȱȱȱ

It has been the Department of Transportation’s and the TSA’s longstanding goal that passengers

should not wait, on average, more than 10 minutes to pass through an airport security checkpoint.

This can be traced back to the objectives laid out for checkpoint efficiency by then Secretary of

Transportation Norman Mineta in 2002 as responsibility for checkpoint screening functions was

being turned over to the TSA.26

The challenge in determining the number of checkpoints that will meet specified wait time

criteria largely derives from the variability and fluctuation in daily and hourly passenger volumes.

Typically a representative busy hour is picked to model the passenger demand for screening. The

TSA has identified a variety of methods for selecting the busy or peak hour to be used in

modeling passenger screening demand. Data can be derived from either annual enplanement

forecasts or from airline flight schedules, with adjustments made for the percentage or amount of

passengers that are transferring from other flights and do not impose demand on the screening

checkpoints.

The number of checkpoints required can then be estimated based on the modeled passenger

demand for checkpoint screening for a representative busy hour divided by the hourly throughput

achievable from a single checkpoint. For example, if the model predicted 3,000 passengers per

hour, and the achievable throughput per screening lane was 300 passengers per hour (five

passengers per minute), then ten screening lanes would provide an optimal number with no

excessive queuing. However, this may result in excessive capacity during non-peak periods. To

better balance resources with reasonable wait times, space requirements for queuing passengers

awaiting to pass through screening checkpoints, known as queue length requirements, can be

assessed by determining passenger average arrival rate over the selected busy hour, multiplied by

the average or expected wait time, divided by the number of checkpoint lanes to process these

passengers.

For example, if it were expected that 3,000 passengers would arrive during the hour, the arrival

rate would be 50 passengers per minute. If the target wait time was 10 minutes, then the total

queue size would be 500 passengers, and in a ten screening lane configuration, that would

translate to 50 passengers in queue per lane. According to design guidelines issued by the TSA,

Remarks of Norman Y. Mineta, Secretary of Transportation, Travel and Tourism Industry Unity Dinner, March 6,

2002, Washington, DC.

ȱȱȱ

ŗśȱ

ȱȱǱȱȱȱ ȱȱȱ

space allocation for queues should provide somewhere between seven and 15 square feet per

person,27 resulting in a total square footage allocation for queuing passengers of between 3,500

and 7,500 square feet in this example.

In this manner, the TSA can determine the optimum number of screening lanes and gauge the

space allocation requirements for queuing passengers to meet peak passenger demand loads.

However, space constraints at airports may prevent achieving these objectives, at least without

overcrowding passengers in queue which can heighten aggravation and tension making it more

difficult to spot suspicious individuals, and it can also heighten security risk because these

overcrowded queues could become prime targets for a shooting or bombing attack. In various

locations, unique airport factors may have a notable impact on the optimum number of screening

lanes as well as the configuration of those lanes. More significantly, airport space limitations and

other factors limiting available resources to set up and staff screening lanes may result in less than

optimal numbers of screening lanes.

Wait time objectives are a key consideration in determining the number of screening lanes and

screeners needed across the nation’s airports. The screening lane requirements, in turn, drive

space requirements at airports for housing security checkpoints and terminal layouts to

accommodate passenger screening operations. The TSA models its staffing allocation and

screening lane requirements using a model that attempts to screen 85% of passengers within the

10 minute target time frame based on passenger volumes projected for each airport’s peak travel

month.28 The TSA notes that on only about 7 percent of days out of the year will passenger

volumes exceed these levels, resulting in expected wait times of more than 10 minutes.

Predictably, many of these days occur during peak travel periods during the Thanksgiving and

Christmas holiday times. While this model, which forms the basis of the TSA’s staffing

allocation, is designed to minimize the number of passengers experiencing waits of more than 10

minutes, in practice many more passengers experience waits of longer than 10 minutes.

At the busiest airports, designated as security category X and category I airports,29 average wait

times have consistently exceeded the 10 minute goal (See Figure 1). Since these larger airports

account for more than three-quarters of passenger boardings, a good portion of airline travelers

routinely experience wait times in excess of the 10 minute goal. While the average wait times at

these large airports are a few minutes greater than the 10 minute target, lengthy wait times,

sometimes exceeding 40 minutes, are not uncommon during peak travel periods at major airports.

However, consistent peak period waits of more than 40 minutes are often grounds for further

examination from a TSA optimization team to identify staffing, screening lane, or other resource

issues that may be contributing to these long waits.30 The GAO has recommended that the TSA

establish a mechanism for periodically assessing the assumptions of its screener staffing

Transportation Security Administration. Recommended Security Guidelines for Airport Planning, Design and

Construction, Revised June 15, 2006.

U.S. Government Accountability Office. Aviation Security: TSA’s Staffing Allocation Model Is Useful for

Allocating Staff among Airports, but Its Assumptions Should Be Systematically Reassessed. February 2007, GAO-07299.

Commercial passenger airports are assigned to one of five security categories (Category X, I, II, III, or IV) based on

consideration of passenger volume and other risk factors. The nation’s busiest airports are assigned to either Category

X or Category I.

U.S. Government Accountability Office. Aviation Security: TSA’s Staffing Allocation Model, February 2007.

ȱȱȱ

ŗŜȱ

ȱȱǱȱȱȱ ȱȱȱ

allocation models as it continues to refine and optimize screener staffing and screening lane

lanes.31

. Average Peak Wait Times at Screening Checkpoints

Figure 1

Average Peak Wait Time (Minutes)

FY2004-FY2006

TSA Target

Airport Security 5

Category:

FY2004

FY2005

FY2006

12.6

Category II

11.8

8.5

11.2

8.3

10.4

7.7

Category III

Category IV

9.1

8.6

8.7

8.2

7.2

Category X

Category I

Fiscal Year

U.S. Government Accountability Office (GAO). Aviation Security: TSA’s Staffing Allocation Model Is

Useful for Allocating Staff among Airports, but Its Assumptions Should Be Systematically Reassessed. February

2007, GAO-07-299.

Source:

ȱȱ ȱȱ¢ǰȱȱȱȱ

ȱ¢ȱȱ

Despite various efforts to improve checkpoint efficiency and reduce passenger wait times,

checkpoint lines remain vulnerable terrorist targets for bombings, shootings, or the potential

release of chemical or biological agents because they often consist of large congregations of

individuals in the “non-sterile” portion of the airport terminal, that is prior to screening for

possible threat items. Inefficiencies at screening checkpoints that result in long screening queues

and congestion in airport terminals introduce unique vulnerabilities that may be mitigated through

various efforts to increase checkpoint efficiency, but may also be mitigated by specific design

considerations to minimize congestion and isolate long screening queues from open, accessible

areas of the airport terminal.

Ibid.

ȱȱȱ

ŗŝȱ

ȱȱǱȱȱȱ ȱȱȱ

Toward this objective, airport and security checkpoint queue design considerations might

consider options for better restricting access to security screening lines and better controlling

access to the areas in and around checkpoint lines to address these vulnerabilities. Additional

streamlining of passenger screening checkpoints may further reduce these vulnerabilities. In

addition to streamlining checkpoint procedures, the TSA is examining ways to integrate next

generation screening technologies as part of its new “checkpoint evolution” initiative.

ȱȱȱȱ

For some time, the responsibility for the passenger screening checkpoint queues has been an

issue. Previously, the TSA had taken a much more limited role in controlling and monitoring the

lines that formed in front of security checkpoints. Airports had the primary responsibility for

controlling access to these lines, and on an airport-by-airport basis, procedures varied for

queuing, including whether to set up dedicated lines for elite travelers (e.g., first and business

class travelers), and for airline crews. Access controls for security screening queues was primarily

a function carried out by airport contract employees serving as document checkers. More

recently, the TSA has been hiring and deploying Transportation Security Officers (TSOs) to serve

as document checkers, eliminating the need for airport document checkers to control access to

screening lines. The TSA has adopted the title of TSOs for the TSA screener workforce to better

reflect the more diversified job functions and roles of these employees, including document

checking, behavioral observation, and bomb appraisal functions. In addition, the continued

expansion of the Registered Traveler program, which potentially offers the opportunity for

streamlined checkpoint processing for passengers who voluntarily submit background

information for vetting by the TSA, is also changing the manner in which screening lines operate.

At many airports, queues to enter checkpoint screening lanes have been designed to provide

“elite” flyer lanes that the airlines make available to first class, and sometimes business class

travelers, as well as to their best customers who have reached certain status levels in airline

frequent flyer programs.32 While the airlines maintain that they have the right to offer elite

passengers curbside-to-curbside perks, including dedicated queues to enter checkpoint screening

lanes, some people have complained that security screening is paid for equally by everyone

through equivalent passenger security fees and general fund contributions, and therefore, all

passengers should receive equal treatment. However, the TSA contends that separating seasoned

passengers familiar with screening procedures from others benefits everyone through better

efficiency and resource allocation at the screening checkpoints.33

More recently the TSA has moved forward with a system of lane self-selection or tailored

screening lanes, allowing expert travelers to select expedited lanes, while families traveling with

small children and individuals needing additional assistance are funneled through screening lanes

better equipped to handle these traveler’s special needs. Also, the Registered Traveler (RT)

program offers paying RT members who have been vetted and issued biometric identity cards

either preemptive queuing or dedicated checkpoint lanes. Whether these concepts will replace or

complement “elite” flyer lanes remains an issue for the TSA, airlines, and airports as they seek to

determine the best model to accommodate travelers and expedite the screening process. The

tailored screening lane initiative and the RT program are described in further detail below.

Sara Kehaulani Goo, “First Class Fast Lane,” The Washington Post, August 2, 2005, p. D01.

Ibid.

ȱȱȱ

ŗŞȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱȱȬȱȱȱ ȱ

In an effort to explore ways to make checkpoint screening queuing processes more efficient and

expedient for passengers, the TSA has field tested an initiative for passengers to self-select among

one of three designated screening lanes based on their knowledge and experience with TSA

screening procedures and the number of carry-on items in their possession. In field tests of this

concept at the Salt Lake City, Utah, airport and Denver International Airport, the TSA has

adopted a skiing analogy, setting up a “Black Diamond” fast lane for expert travelers that are

completely familiar with screening procedures and are traveling with a single carry-on bag. A

“Blue Square” lane has been designated for frequent flyers somewhat familiar with TSA

procedures, or more experienced flyers that have multiple carry-on items. Finally, a “Green

Circle” lane has been established for families with small children, parents carrying infants and

toddlers in strollers, others needing special assistance, as well as those unfamiliar with checkpoint

security procedures that require additional guidance.

For some travelers, lane selection is constrained. For example, those carrying multiple bags

would not be allowed to choose the Black Diamond lane, and those traveling with small children

or strollers would be routed to the Green Circle lane. However, other travelers would be free to

self-select their lane. For this reason, choosing a Black Diamond lane might not always be the

fastest route if it is often chosen, particularly if it is chosen by individuals that really don’t have a

full understanding of the security screening procedures and restrictions. This could lead to

frustration and aggravation among delayed passengers expecting a streamlined process by

choosing the expert lane. While this is a difficult issue to address, passenger checkpoint

experiences among all travelers, including expert travelers, may be improved though passenger

education.

Nonetheless, the TSA has noted that in the trial program, passengers choosing the Black Diamond

lanes have experienced significantly reduced wait times. Smoother operations in other lanes have

also been observed. For example, the TSA attributes a reduction in the confiscation of prohibited

items to families feeling less rushed and having more time to prepare for the screening process.

The TSA contends that “[s]ecurity is best served by a calm screening environment ...”34 and has

indicated that it is seeking to expand this initiative to additional airports that will be selected

based on airport and airline support, and consideration of checkpoint configuration and passenger

characteristics.35 By the end of FY2008, the TSA had expanded the use of these self-select lanes

to 32 airports. According to TSA observations, since implementing the program, expert lanes

have seen an average 21 percent increase in throughput (with some as high as 40 percent), while

alarm rates for lanes designated for families and those needing extra assistance have been reduced

by an average of 11 percent.36 Based on these results, the TSA has expanded the use of self-select

lanes at several airports throughout the United States.

Transportation Security Administration, TSA Announces Expansion of ‘Diamond’ Self-Select Lanes. Press Release,

March 5, 2008.

Ibid.

Transportation Security Administration, Black Diamond Self Select Lanes, Helping Passengers Move at Their Own

Pace.

ȱȱȱ

ŗşȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱȱȱȱ

In addition to the tailored self-select screening lane initiative, the TSA regards the Registered

Traveler (RT) program as another potential means to streamline checkpoint processing of

participating passengers that pose a known low risk, allowing the TSA to better concentrate its

resources on screening passengers of unknown or elevated risk (e.g., conducting secondary

screening of passengers selected based on similar name matching to suspected terrorists, terrorist

sympathizers, or supporters of terrorist organizations; resolving alarms that occur during primary

screening; and assessing the risk of passengers exhibiting suspicious behaviors). The registered

traveler concept was recommended by airlines and airports soon after the 9/11 attacks as a means

to vet trustworthy travelers and allow security screening efforts to concentrate on those

passengers of unknown risk, or particularly, passengers posing an elevated risk. It was initially

believed that such a system could encompass most of the flying public, allowing security

screening efforts to be highly focused on those travelers that were not part of the program. Within

weeks after the 9/11 attacks, the DOT’s Airport Security Rapid Response Team included among

its recommendations the urgent need to establish a nationwide program for voluntarily submitting

information for vetting passengers who would be issued “smart” credentials, to expedite

processing of the vast majority of travelers, thus allowing aviation security resources to be

focused most effectively, an idea that became known as the “trusted traveler” concept. The

recommendation was reflected in statutory language included in the Aviation and Transportation

Security Act (ATSA; P.L. 107-71) and gave the TSA the authority to pursue a voluntary system

for passenger vetting and identity authentication using biometrics.

To date, the RT program has been quite limited in its scope, available primarily to frequent

travelers at a small number of airports under a trial program. As of December 2007, the TSA

estimated that about 64,000 individuals were participating in the RT trial program, only a very

small fraction of the tens of millions of annual airline travelers. The TSA, however, began

expanding the RT program in the summer of 2008 beyond the original 19 airports that

participated in the trial program. RT is now available to any airport that requests it.

The RT program was originally implemented under a public-private partnership model, in which

volunteer passengers, who submit background information for vetting along with biometric data,

are issued biometric identity cards issued by private service providers once cleared through the

background check process, which is coordinated by the TSA. The TSA has since dropped the

background check process and now describes the RT program as strictly a private sector

enterprise.37 The RT vendors are responsible for card issuance and identity verification of

program participants as they enter screening checkpoints, however security screening remains the

responsibility of the TSA.

In some airports, RT participants are simply given preemptive queuing into screening lanes used

by all other passengers, while other airports have dedicated screening lanes for RT program

participants. Additionally, at some airports, like Orlando International Airport (MCO), RT

program participants have been used to test out emerging technologies, like shoe scanners,

allowing them to reduce or eliminate some of the hassles associated with passenger screening.

The concept has been to provide RT participants with some sort of expedited screening

experience as an incentive for participation. In turn, the TSA was expected to benefit by

Transportation Security Administration, “Registered Traveler Interoperability Pilot Program,” Federal Register,

73(147), July 30, 2008, pp. 44275-44278

ȱȱȱ

ŘŖȱ

ȱȱǱȱȱȱ ȱȱȱ

maintaining basic screening requirements for RT participants, thus allowing it to better focus

more extensive resources on non-participating passengers that pose an unknown or elevated risk.

However, the TSA has largely concluded that current technologies are not advanced enough to

offer RT participants an opportunity to bypass minimal screening requirements, because the

required background checks do not eliminate the possibility that an RT participant could take

hostile action threatening aviation security, and that the main benefits of the RT program are its

identity verification capabilities.38

From its experience during pilot testing, the TSA determined that the security threat assessment

conducted on RT applicants is largely redundant with terrorist watchlist checks conducted on all

passengers each time they fly, and found that other elements of the background check performed

“are not core elements in determining threats.”39 Therefore, under the fully deployed RT program,

the TSA decided to eliminate the additional elements of the background check process and do

away with the $28 fee it passed on to RT applicants to offset related costs.40 While the RT

program is now available to all airports, its future now seems uncertain as the benefits to both the

TSA and program participants based on experience during testing appear to be much more limited

than originally anticipated.

Moreover, just as the TSA announced nationwide availability of the RT program in the summer of

2008, it took action to suspend Verified Identity Pass, Inc., which serves as a vendor for the RT

program under the brand name Clear®, from processing new applications after a laptop computer

containing unencrypted applicant personal data from about 33,000 RT applicants was reported

missing from San Francisco International Airport (SFO). This potential data breach prompted the

TSA to suspend further enrollment in the Clear® Identity Pass RT program while it conducted

audits of Verified Identity Pass, Inc., data security procedures. The suspension was quickly lifted

after the laptop was recovered and the company put in place procedures to encrypt all enrollee

personal data.41 The incident and the potential threat of data breaches, however, raise considerable

questions about the protection of private information under such programs during a time when

there is considerable anxiety over identity theft. Security breaches such as this may cause

potential applicants to reconsider whether the potential benefits of moving more quickly through

security lines with fewer hassles are worth the risk of potential identity theft. Data security,

therefore, appears to be another key issue for the future direction of the RT program.

Questions also remain regarding how hassle-free RT security lines are and how much time RT

participants really save at security checkpoints. According to the TSA, it is up to individual

airports to determine if they wish to participate in this program. As TSA moves forward with RT,

the airline industry, which once backed this program as a means to reduce hassles for frequent

fliers, now characterizes the manner in which it is being implemented as having limited and

questionable benefit. The use of the program as a testbed for streamlined screening technologies

and procedures has thus only provided limited benefits and reductions in travel hassles to

participants. Nonetheless, some RT vendors have been pushing forward with the concept of

Ibid.

Transportation Security Administration, “TSA Lifts Cap and Eliminates Fee on Registered Traveler,” Press Release,

July 24, 2008.

Transportation Security Administration. “Registered Traveler Interoperability Pilot Progam,” Federal Register, 73

(147), July 30, 2008, pp. 44275-44278.

Transportation Security Administration, “Update On Verified Identity Pass, Inc. Clear®’s Registered Traveler

Enrollment,” Press Release, August 11, 2008.

ȱȱȱ

Řŗȱ

ȱȱǱȱȱȱ ȱȱȱ

promoting the RT program as an opportunity to stimulate the development of advanced screening

technologies, particularly technologies that can improve checkpoint efficiency. For example,

Verified Identity Pass, Inc., has offered technology developers a $500,000 prize for the

development of technologies that can further streamline checkpoint processes, focusing on the

scanning of shoes, laptops, and outer garments.42 The company indicates that it would pursue

partnerships with the winning developer to obtain TSA certification of promising new

technologies and would ultimately seek to purchase systems for screening RT participants.

While the potential benefits of the RT program have not been fully realized, Congress included

language in the FY2008 Consolidated Appropriations Act (P.L. 110-161) directing the TSA to

establish an international RT program that incorporates biometrics and e-passport technologies to

be used in conjunction with US VISIT and the Visa Waiver Program. Under the existing RT

program, some international carriers have been participating for outbound flights originating from

JFK and Newark Liberty airports. The future of both domestic and international RT

implementation remains an issue of particular interest with regard to how this program may be

able to someday work in coordination with other screening initiatives to streamline the process

for certain passengers, thereby facilitating a risk-based allocation of screening resources to focus

on those passengers that present an unknown or elevated risk.

ȱȱȱȱȱȱ

Additional efficiencies may be gained in passenger checkpoint screening if some current

requirements could be met using more expedient alternatives. Two procedural requirements in

particular are believed to be major factors in decreasing passenger throughput and increasing the

so-called hassle factor: the requirements to remove shoes for X-ray screening and the requirement

to remove laptops and other large portable electronics, such as portable DVD players, from carryon baggage so that they can be screened separately. Eliminating these requirements, or taking

steps to streamline these aspects of the screening experience, is therefore seen as having a

potentially significant impact on improving checkpoint efficiency.

Shoe scanners that may eliminate the need to remove shoes for scanning were initially tested on

participants in the Registered Traveler (RT) pilot program in 2007. However, the model

manufactured by GE tested under the RT program was found to not meet TSA’s detection criteria

and further testing of the systems was suspended.43 In August 2008, the TSA initiated field testing

of a different model shoe scanner, the L3 PassPort, at Los Angeles International Airport. The shoe

scanner systems currently under evaluation use explosives trace detection methods and puff air

over the shoes to collect samples for analysis.44 The systems are designed to detect traces of

nitrate-based and peroxide-based explosives, but they do not generate an image of the shoe or

screen for metals.45 During these trials, the TSA will still require passengers to remove their shoes

after being scanned by the machines to make sure the technology does not miss any explosives

“Clear Offers 500K Prize for New Checkpoint Technology,” Aviation Week’s Airports, 26(1), January 8, 2008, pp.

1-2

Transportation Security Administration. “Status Update on Testing of General Electric Kiosk for Registered

Traveler,” News & Happenings, TSA, October 9, 2007.

Benet Wilson, “TSA Tests L3 Shoe Scanners at LAX Airport Checkpoints,” Aviation Daily, August 7, 2008.

Steve Surjapurta, “May We Leave Our Shoes On at Airport Security?,” Tripso Travel News, August 1, 2008.

ȱȱȱ

ŘŘȱ

ȱȱǱȱȱȱ ȱȱȱ

threats.46 However, pending the outcome of these trials, shoe scanners may eventually be

deployed to airports nationwide potentially allowing most passengers to keep their shoes on

during the entire screening process.

The TSA is also in the process of approving designs for laptop carrying cases that are specifically

designed to allow laptop computers to remain in the bag as they pass through the X-ray scanner.

The TSA requires that the bag designs provide an unobstructed X-ray image of the laptop

computer by itself.47 This is accomplished through the use of a pull out or flip out laptop sleeve or

compartment that allows the laptop to be scanned by itself, away from the other compartments

and contents of the carry-on. Passengers will be instructed to place only the laptop in this sleeve

to avoid the laptop image from being obscured by power cords, peripheral devices, or other items

stowed in the carry-on bag. Since use of the TSA-approved laptop cases is voluntary and requires

an investment by travelers, it may be some time before this has any meaningful impact on

improving checkpoint efficiency. For laptop-toting travelers, however, the reduced hassle of not

having to remove then re-pack laptop computers may been seen as a considerable incentive by

itself to purchase one of these cases, even if it doesn’t guarantee shorter wait times at screening

checkpoints in the near term.

ȱȱȱȱ

In addition to checkpoint delays caused by laptop and shoe screening requirements, the TSA

limitation on liquids carried through security checkpoints, implemented in 2006, has resulted in

considerable confusion, delays, and hassles for airline passengers and has had a significant impact

on checkpoint efficiency and passenger wait times.

Immediately following the detection of the terrorist plot targeting airliners bound for the United

States and Canada from London’s Heathrow Airport in August 2006, the TSA responded by

banning the carriage of all liquids and gels by passengers through airport screening checkpoints.

The total ban on liquids and gels remained in effect for several weeks. During this period, limited

exceptions were made for breast milk for babies, liquid medicines, and other liquids regarded as

being medically necessary. Beverages purchased beyond the screening checkpoint were not

included in the ban, largely because the threat of passing bomb-making materials to an airline

passenger using liquids purchased from vendors in the secured areas of airport terminals was

considered minimal, and other security measures, such as background checks for airport workers,

were viewed as limiting the possibility that terrorists might exploit beverage distribution to

airport vendors as a means to get liquid explosives beyond airport security checkpoints.

In September 2006, the TSA relaxed the passenger liquid ban to some degree, establishing

specific quantity limits and special procedures for carrying liquids through screening checkpoints.

The TSA ultimately settled on a procedural approach for passengers to carry limited quantities of

liquids through checkpoints and onto aircraft in a manner facilitating screening and inspection of

those liquid items. The TSA refers to these procedures as the “3-1-1 for carry-ons” concept, with

the objective of providing a simple-to-remember memory aid for travelers. Under 3-1-1, travelers

are allowed to carry through the checkpoint liquids in bottles with a liquid volume of three

Art Marroquin, “Airport Security to Test Shoe Scans,” LA Daily News (Los Angeles, CA), August 2, 2008.

Transportation Security Administration, “New Security Simplifying Laptop Bag Procedures,” TSA News &

Happenings, July 29, 2008.

ȱȱȱ

Řřȱ

ȱȱǱȱȱȱ ȱȱȱ

ounces or less, are limited by how many of these bottles will comfortably fit within a one quart

clear plastic bag, with a limit of one such bag per traveler.

By November 2006, the European Union, along with Canada and other countries in Europe, Asia,

and the South Pacific, adopted the 3-1-1 protocols in an effort to harmonize international aviation

security procedures with TSA procedures. The TSA believes that roughly half of the world’s

aviation travelers must adhere to these procedures for carrying liquids through security screening

checkpoints.

The 3-1-1 procedures were designed to allow the carry-on of liquid toiletry items in specified

quantities for those passenger traveling on short trips and not checking baggage and for making

reasonable accommodations to allow for accessible liquid medicines and toiletry items on longer

flights. However, placing liquids in checked baggage is still preferred by the TSA. In addition to

these allowable liquids, passengers are allowed to bring on board liquid medicines, as well as

baby formula and food, breast milk, and juices to provide for a traveling infant. These items are

allowed in reasonable quantities exceeding the three ounce limit imposed on other liquids and are

not required to be placed in the quart-sized bag. While these procedures have been designed to

provide reasonable accommodations for passengers traveling on short trips or with special needs

for access to liquid medicines, necessary dietary supplements, and items to care for infants, the

procedures often cause confusion and delays at airport screening checkpoints. The TSA has made

extensive efforts to educate and inform the public regarding these procedures, and has been

exploring the use of tailored screening lanes to separate passengers that might be unfamiliar with

these procedures from seasoned air travelers seeking an expedited process to get through airport

screening.

The TSA has responded to public criticism over the liquids ban and subsequent 3-1-1 procedures

by pointing out the significance of the liquids explosives threat. However, an aspect of the liquids

ban that has raised considerable criticism of the TSA is that the threat posed by liquid explosives

was widely understood prior to the U.K. liquids bombing plot. Liquid explosives had been used

in the downing of Korean Airlines flight 858 in November 1987, and Ramsi Yousef used an

improvised liquid explosive device to bomb Philippine Airlines Flight 434 in December 1994,

smuggling the chemicals onboard in a contact lens solution bottle. He and his co-conspirators

were plotting to use similar liquid explosive devices, assembled in the aircraft lavatory, to destroy

as many as twelve U.S.-bound aircraft from Asia as part of the so-called Bojinka plot concocted

by Yousef and his uncle, Khaled Sheikh Mohammed. Authorities believe that the U.K. liquids

explosives plotters similarly sought to assemble liquid explosive devices in aircraft lavatories, but

unlike the Bojinka plot, intended to carry out suicide attacks, killing themselves along with all on

board these aircraft. Despite the previous attacks involving liquid explosives, it was only after this

plot was uncovered by British authorities that the TSA felt compelled to take action and impose

significant constraints on the carriage of liquids through screening checkpoints and onboard

aircraft.

While it appeared unlikely that security procedures for carrying liquids on board aircraft would be

significantly modified or relaxed anytime soon – until new technologies capable of reliably

detecting liquid explosives could be developed, tested, and fully deployed at airports – the TSA

announced that it would begin phasing out restrictions on carry-on liquids by the fall of 2009.48

Former TSA Administrator Kip Hawley indicated that, by the end of 2010, passengers should be

Thomas Frank, “TSA likely to ease restrictions on liquids in 2009,” USA Today, October 28, 2008.

ȱȱȱ

ŘŚȱ

ȱȱǱȱȱȱ ȱȱȱ

able to again carry liquids through screening checkpoints, but would be required to place bottles

and other liquid containers through X-ray machines separately.

ȱȱȱ ȱȱ

The TSA has launched several initiatives to inform the public regarding specific checkpoint

requirements, procedures, and limitations. The efforts to inform passengers regarding the 3-1-1

policy on liquids serves as an example of how the TSA has made considerable efforts to provide

the traveling public with adequate information regarding screening and security procedures to

make passengers experiences as efficient and hassle-free as possible, given current policies,

strategies, and approaches to screening. However, many security procedures remain confusing, in

part, because they have changed in response to changing threat assessments, or have been applied

inconsistently in the past.

Public education is likely to increase in importance as the TSA rolls out various new checkpoint

screening technologies over the next several years. While some of these technologies have been

field tested on a limited basis at various airports across the country, ongoing initiatives to deploy

these systems nationwide represent the most significant change to the passenger checkpoint

experience since mandatory use of magnetometers and X-ray screening of carry-on items was

implemented 35 years ago.

ȱȱȱȱ ȱ

To address the challenges of improving screening performance, enhancing the capability to detect

explosives, and increase checkpoint efficiency and throughput, the TSA is testing new checkpoint

concepts that integrate emerging screening technologies and address various operational and

human factors needs. In March 2008, the TSA launched an initiative called Checkpoint Evolution

encompassing a variety of planned improvements to airport screening checkpoints. Former TSA

Administrator Kip Hawley noted that “[t]his is the first significant change to the checkpoint since

the 1970s,” a reference to the fact that the layout of airport screening checkpoints in the United

States, has remained relatively unchanged since they were first implemented in the early 1970s.

A Checkpoint Evolution Team at the TSA has developed a prototype concept for the checkpoint

of the future that is showcased on the TSA website.49 The prototype future checkpoint concept

entered operational testing and evaluation at Baltimore Washington International Thurgood

Marshall Airport (BWI), in Terminal B, which services Southwest Airlines, in April 2008. This

prototype includes multiview AT X-ray equipment, millimeter wave whole body imaging (WBI)

portals used for continuous random screening, and liquid bottle scanners.50 However, the

investment strategy and deployment schedule for deploying various future checkpoint concepts

currently under evaluation remains unclear.

In addition to potentially improving the efficiency and effectiveness of the screening process,

proposed changes to the screening checkpoint may help reduce congestion at “soft target”

See [http://www.tsa.gov/evolution/index.shtm]

Transportation Security Administration. “Checkpoint Changes to Improve Security and Calm Process,” TSA News &

Happenings, April 28, 2008.

ȱȱȱ

Řśȱ

ȱȱǱȱȱȱ ȱȱȱ

locations such as airport lobbies. Various design elements of the proposed future checkpoint

provide potential mitigation of the threat of explosives carried through the security checkpoint

and possibly for the threat of shootings or bombings in and near the checkpoint queue. By

designing more streamlined queuing process, and queuing areas that are better separated from the

public spaces in the airport terminal, the TSA hopes to achieve enhanced capabilities for

surveillance and behavioral detection of potential threats of this kind.

The TSA is also seeking to implement methods to make the screening checkpoint a calmer, less

chaotic environment in hopes that this will allow screeners and behavioral detection officers

(BDOs) to more easily spot suspicious behaviors. Former TSA Administrator Kip Hawley noted

that “[c]alm allows things to stand out more. It creates a better environment to observe hostile

intent.”51 According to the TSA, a calmer checkpoint environment can also help to ease perceived

time pressures and other distractions that may hinder screener performance.

Elements of the future screening checkpoint queuing area design include mood lighting, soothing

music, improved signage to direct and instruct passengers, and museum-style storyboards that

convey personal stories of various TSA screeners. In the prototype, panels and informational

boards also function as barriers to better separate the checkpoint queue from the rest of the

passenger terminal. The queuing area also includes a “prep stop,” giving passengers a location to

discard or recycle any trash or prohibited items, such as beverages, and organize and bag other

items prior to screening. Travel document checking stations, staffed by TSA document checkers,

are to be positioned at the transition between the queue and the screening lanes.

In the screening lanes, various technologies and procedures to streamline the screening process

are included in the future checkpoint concept. For processing carry-on bags, the prototype system

integrates an automatic conveyor and bin return system. The proposed automated conveyor

system is to have the capability to separate alarm items (i.e., suspicious items that require

additional scrutiny) from cleared carry-on items. Cleared items are to proceed down the conveyor

to a collection area where passengers can gather their possessions.

One highlighted feature of the prototype system is the use of sensitive cameras in the collection

area to identify and alert passengers when items, including items as small as coins, are left behind

in the conveyor bins. Once the bins are emptied, the system would automatically return them via

a reverse-direction conveyor belt to the beginning of the conveyor for reuse, thus eliminating the

labor-intensive function of moving and stacking bins currently performed by TSOs.

On the back end of the future checkpoint configuration, the TSA plans to install “re-composure

benches,” to allow passenger to reassemble their items that may have been removed or opened

during the screening inspection process, and an “end zone” where travelers can regroup with their

families or others traveling with them before proceeding to their boarding gate.

Two significant challenges to implementing the proposed checkpoint evolution concept are

acquisition and sustainment costs and airport space requirements. The Bush Administration’s

Budget Request for FY2009 specified $11.5 million for checkpoint reconfiguration and expansion

costs, matching FY2008 levels. However, much of this has been slated for expanding the number

of screening lanes at various airports across the country to meet the expected growth in passenger

air travel rather than for reconfiguring existing screening lanes. Future funding needs to

Thomas Frank, “TSA Tries Soothing Screening Process,” USA Today, March 30, 2008.

ȱȱȱ

ŘŜȱ

ȱȱǱȱȱȱ ȱȱȱ

implement checkpoint evolution concepts beyond initial field testing is yet to be determined.

These checkpoint evolution concepts are currently being field tested in conjunction with other

initiatives to deploy next generation checkpoint screening technologies aimed at addressing

lingering concerns over the limited ability to detect explosives on passengers and in carry-on

items.

¡ȱ ȱȱȱ

Since the early 1970s, passenger screening checkpoints have relied almost exclusively on the use

of magnetometers, or walk-through metal detectors (WTMDs), as the sole means for primary

screening for weapons or other prohibited or dangerous items being carried by passengers. These

machines induce pulsed magnetic fields and sense any interruption or disturbance in those fields,

usually caused by the presence of metallic objects, as individuals pass through these fields.52

These devices, however, are not capable of detecting explosives or nonmetallic threat items. Also,

checkpoint screening of carry-on items for explosives, weapons, and other threats is carried out

using X-ray systems are limited in their ability to assist human operators detect objects or make

determinations regarding potential threat objects based on the X-ray image.

In its final report, the 9/11 Commission recommended that “[t]he TSA and the Congress must

give priority attention to improving the ability of screening checkpoints to detect explosives on

passengers.”53 Congress responded by including language in the Intelligence Reform and

Terrorism Prevention Act (P.L. 108-458), directing the Department of Homeland Security to “...

give a high priority to developing, testing, improving, and deploying, at airport screening

checkpoints, equipment that detects nonmetallic, chemical, biological, and radiological weapons,

and explosives, in all forms, on individuals and in their personal property.”54 The legislation also

directed the TSA to develop a strategic plan for deployment of explosives detection equipment at

airport checkpoints, including technologies such as walkthrough explosives detection portals,

document scanners, shoe scanners, and X-ray backscatter devices. These various technologies are

discussed in further detail below. The Implementing Recommendations of the 9/11 Commission

Act of 2007(P.L. 110-53) reiterated the requirement for developing this strategic plan, and also

established a Checkpoint Screening Security Fund, requiring that $250 million collected from

passenger and airline security fees be deposited in this fund in FY2008. Funding for Checkpoint

Support, which encompasses checkpoint technology acquisition has been maintained at the $250

million level for FY2009 (See P.L. 110-329).

Over the past few years, the TSA has been field testing a wide variety of checkpoint technologies

aimed at improving the screening of passengers and carry-on items, particularly to address the

need for improving the detection of explosives at passenger checkpoints. A summary of some of

the key emerging checkpoint technologies that are now reaching technical maturity for field

testing and deployment in airport settings is provided in Table 1. A more comprehensive

examination of screening technologies and technical approaches follows. These technical

approaches include explosives chemical trace detection methods; whole body imaging systems;

Tim L. Hudson and Matthew J. Frankel, “Staying Ahead of the Game: The Future is Now for Advanced Passenger

Screening,” Airport Magazine, April/May 2007, pp. 46-50.

National Commission on Terrorist Attacks Upon the United States. The 9/11 Commission Report (Authorized

Edition). New York, NY: WW. Norton & Company. p. 393.

P.L. 108-458, Sec. 4013; 49 U.S.C. §44925.

ȱȱȱ

Řŝȱ

ȱȱǱȱȱȱ ȱȱȱ

advanced technology X-ray capabilities; and other methods, such as computed tomography (CT)based explosives detection systems (EDS) and the use of magnetic resonance imaging (MRI)

technologies for detecting explosives and other threat objects in carry-on items.

Table 1. Emerging Checkpoint Technologies

Emerging Technology

Description

Advanced Technology (AT) X-Ray

X-ray systems with advanced visual

detection capabilities including multiview imaging and automated

explosives detection algorithms

Imaging systems using X-ray

backscatter or millimeter wave

(mmW) imaging technologies to

inspect for concealed weapons and

explosives under passenger clothing.

These units can be used in place of

metal detection wands and physical

pat-down inspections

A new handheld detection capability

to discriminate explosives or

flammable liquids from common

benign liquids carried by passengers

or in carry-on items

Specially designed low dose X-ray

backscatter devices to screen casts

and prosthetic limbs for possible

concealed weapons and certain

explosives

Devices to scan shoes for explosives

using nuclear quadrupole resonance

imaging techniques. Field tested

under the Registered Traveler

Program but found to not yet meet

minimum detection standards

Walkthrough portals using explosive

trace detection methods to inspect

passenger for trace indicators of

explosives.

Automated detection capability for

inspecting bags for explosives and

weapons using computed

tomography (CT) based solutions.

Seen as a possible means for either

complementing or replacing current

manual X-ray image analysis

processes

Whole Body Imagers (WBIs)

Bottle Liquid Scanners (BLS)

Cast and Prosthesis Imagers

Shoe Scanner Systems

Explosives Trace Detection Portals

Automated Carry-On Bag Explosives

Detection System

Source:

Estimated Per Unit Acquisition

Cost

$199,845

$256,872

$42,419

$56,567

$ Not Specified

$211,924

$506,778

Transportation Security Administration, Congressional Justifications – Aviation Security, FY2008 and

FY2009.

ȱȱȱ

ŘŞȱ

ȱȱǱȱȱȱ ȱȱȱ

¡ȱȱȱȱ

Several technologies that use various explosives trace detection methods are available for

screening passengers and carry-on items for explosives. Available explosives trace detection

technologies that may be considered for checkpoint use include explosives trace detection (ETD)

machines tailored for checkpoint screening lane use to screen carry-on items; handheld bottled

liquids scanners that use explosive trace detection screening methods; and walk-through

explosives trace detection portals for screening individuals.

¡ȱȱȱǻǼȱ

ETD machines have been a fixture at aviation screening checkpoints and for checked baggage

screening at smaller regional airports since the TSA assumed responsibility for passenger

screening. These systems are capable of detecting minute quantities of elements found in

explosive compounds using a variety of techniques, including mass spectrometry, gas

chromatography, chemical luminescence, and ion mobility spectrometry,55 to measure the

chemical properties of vapor or particulate matter sampled from passengers, carry-on items,

checked baggage, or cargo. It is generally believed that ETD systems will continue to play a

central role in the screening of carry-on items to detect traces of explosives for items belonging to

individuals singled out for secondary screening, or items flagged for additional screening based

on the analysis of the TSA screener viewing the X-ray image of the item during the primary

screening process.

ȱȱȱ¡ȱȱ

Following the August 2006 U.K. aircraft liquid bombing plot, the TSA has been keenly interested

in identifying an effective technology for detecting explosives in liquids and flammable liquids

without requiring direct contact with a sample. Observers have noted that it would have been

extremely difficult to detect liquid explosives, like those the terrorists had planned to use,

employing checkpoint screening technologies and techniques in place at that time.56 Since then,

the TSA has been working with a number of vendors of bottled liquid scanner (BLS) technology

to identify candidate systems for field testing.

So far, two handheld units, the Fido PaxPoint developed by ICx Technologies and the SABRE

4000 developed by Smiths Detection have been acquired by the TSA for field testing. The

SABRE 4000 relies on ion mobility spectrometry, a common trace detection method proven

effective in detecting minute quantities of explosives and chemical weapons. The Fido PaxPoint

uses a different trace detection technology that relies on amplifying fluorescent polymers, a

technique that utilizes a film lining that reacts when exposed to minute quantities of explosives.

The sensitivity of these devices is considered to be sufficient enough to detect explosive traces

and vapors through bottles and other sealed containers, including peroxide-based explosives as

well as nitrogen-based explosives. These units cost roughly $43,000 each. Under the TSA’s

proposal for FY2009, it intends to deploy a cumulative total of 250 of these units, which would

enable them to be available at roughly two-thirds of all screening lanes at Category X and

These terms refer to a variety of techniques used to identify unknown chemical compounds that are applied in the

aviation security setting primarily, and often exclusively, to test for the presence of explosives.

Norman Shanks and Steve Wolff. “The Liquid Bomb Threat.” Air Safety Week, August 21, 2006, p. 1.

ȱȱȱ

Řşȱ

ȱȱǱȱȱȱ ȱȱȱ

Category I airports. This, however, is considerably scaled back from earlier estimates that the

TSA would acquire a cumulative total of 800 of these units by the end of FY2008.57 Both devices

have been deployed in field tests at several large airports.

While these devices also have the capability of detecting chemical warfare agents, it appears that

the TSA is primarily interested in the explosives detection capabilities of these devices and has

not formally addressed the potential threat of chemical attacks in airline passenger cabins,

although chemicals like Sarin and VX nerve agent have been used in non-aviation terrorist attacks

in the past.

The TSA has also considered various other technologies capable of detecting liquid explosives

through a sealed container that use X-ray quadrupole resonance imaging, acoustic/ultrasound,

Raman spectroscopy, and electromagnetic resonance techniques. Researchers are also working on

laser irradiation techniques for detecting peroxide-based explosives.58 These various techniques,

however, can encounter difficulty in accurately identifying explosives through opaque containers

and tend to yield relatively high numbers of false positives making them impractical for

deployment at airport screening checkpoints given the current state of technology maturity of

these systems.59

ȱ¡ȱȱȱ

In 2004, the TSA initiated pilot testing of walkthrough explosives trace detection portals. When

passengers pass through these semi-enclosed portals, puffs of air are blown at them to provide

airborne samples of elements on their person. The samples are automatically collected and

analyzed by the unit to detect the presence of explosives using explosives trace detection

techniques. The system relies on an ion mobility spectrometry process that provides versatile

detection of both positive and negative ions using a proprietary ion “trap.”60 The system is

capable of detecting a broad spectrum of explosives in a matter of a few seconds. However, citing

reliability problems, the TSA suspended further deployment of these systems, and was reportedly

reassessing how to proceed.61 The TSA has not sought to acquire additional trace portal systems,

focusing instead on testing and deployment of whole body imaging (WBI) technologies, which

are discussed in further detail below.

ȱ¢ȱ ȱȱ

As part of the TSA’s overall approach to improving the detection of explosives and nonmetallic

weapons at passenger screening checkpoints, it is currently exploring the use of whole body

imaging technologies for detecting concealed items carried by passengers. Whole body imaging

solutions offer an integrated approach to passenger screening insofar as these technologies can

reveal concealed items carried on a person, including traditional metallic weapons, non-metallic

“TSA Adds More Bottle-Screening Devices at Airport Checkpoints.” Aviation Daily, November 16, 2007.

“New Analytical Tool Developed for Liquid Explosives Detection.” Science Daily, October 13, 2006.

Kevin Bullis, “A Better Liquid-Explosives Detector,” MIT Technology Review, December 1, 2006.

General Electric, “The United States Transportation Security Administration (TSA) has installed the GE EntryScan³

Walk-through Explosives Detector to Screen Passengers at Boston Logan Airport’s Terminal a Security Checkpoint.”

September 9, 2006.

Eric Lipton, “Screening Tools Slow to Arrive in U.S. Airports,” The New York Times, September 3, 2006.

ȱȱȱ

řŖȱ

ȱȱǱȱȱȱ ȱȱȱ

weapons, and explosive devices. These systems, however, cannot provide an indication of

whether a concealed item is made of explosives material. Nonetheless, detection of a concealed

item can alert screeners to conduct more thorough screening to determine the specific

characteristics of the item through methods such as explosives trace detection or walkthrough

explosives detection portals.

The TSA is continuing to study specifically how whole body imaging technologies could be

integrated with other technologies in future checkpoint screening solutions. The Transportation

Security Laboratory (TSL), a component of the DHS Science and Technology Directorate, has

been mulling a concept it refers to as the “tunnel of truth.” This future checkpoint concept, which

would submit passengers to a battery of screening techniques while being transported on a

moving walkway, incorporates whole body imaging technologies along with trace detection portal

technologies.62

Because of the ability to detect a broad array of concealed items, many view whole body imaging

systems as a candidate technology for primary screening as part of a system such as the future

“tunnel of truth concept,” although in current field testing the TSA is providing this technology

solely as an option for passengers selected for secondary screening as an alternative to a pat-down

search, and as a procedure applied to individuals randomly selected for secondary screening.

Since whole body imaging technologies are regarded by some as highly invasive, critics of these

systems have argued that they should only be used in limited circumstances. For example, the

American Civil Liberties Union (ACLU) has urged Congress to ban the use of whole body

imaging technologies as a method for primary screening. The ACLU maintains that “[p]assengers

expect privacy underneath their clothing and should not be required to display highly personal

details of their bodies.”63 The ACLU has also raised concerns that, if used as a primary screening

method, whole body imaging technologies would, in their opinion, cause unnecessary delays by

increasing the number of questionable items detected on persons passing through the checkpoint

that would need to be resolved through additional screening techniques such as explosives

detection portals and conventional metal detectors. The ACLU maintains that these technologies

require “a tremendous invasion of privacy with little speed or efficiency gains.”64

It should also be noted that while these technologies may be considered by some as being more

invasive, they offer a potential capability for detecting nonmetallic threat items, particularly

explosives, that does not currently exist with magnetometer screening. In this regard, WBI

systems directly address 9/11 Commission recommendations and congressional mandates to

develop and deploy capabilities to detect nonmetallic threat items at airport screening

checkpoints. It is therefore, arguably inappropriate to directly compare these whole body imaging

systems to current screening checkpoint operations that do not have the capability to address

these mandates.

The TSA is currently field testing two candidate whole body imaging technologies for use in

detecting explosives and non-metallic weapons carried by passengers. The first of these

“TSA Tunnel of Truth May Come Your Way,” Airport Magazine, August/September 2008, p. 66.

Statement of Timothy D. Sparapani, ACLU Legislative Counsel, Before the Senate Committee on Commerce,

Science, and Technology, Regarding the U.S. Transportation Security Administration’s Physical Screening of Airline

Passengers and Related Cargo Screening, April 4, 2006.

Ibid.

ȱȱȱ

řŗȱ

ȱȱǱȱȱȱ ȱȱȱ

technologies is known as X-ray backscatter technology and involves images generated by

detecting radiation reflected off objects irradiated with X-rays. The second technology, millimeter

wave (mmW) imaging technology generates images by examining reflections of extremely high

frequency electromagnetic waves. Both technologies have the capability of penetrating objects

that can normally conceal objects in a visual scene, including clothing, baggage, and even steel

containers and automobiles. Broadly speaking, both of these technologies offer the potential for

unobtrusive monitoring and scanning capabilities for security applications, including possible

covert scanning applications in the aviation security context and perhaps in other security

applications.

In addition to potential use at airport screening checkpoints, both X-ray backscatter and

millimeter wave technologies are also being considered for screening air cargo, carry-on items,

checked baggage, and also for screening vehicles parked near airport terminals and vehicles

entering access-controlled areas. While there is a broad array of potential security applications for

these technologies, this discussion focuses on the use of these technologies for screening

passengers at airport screening checkpoints. Identified concerns over this specific application of

either of these competing technologies include protection of personal privacy, ability to detect

items hidden in private and concealed areas on an individual, and possible health concerns

regarding exposure to radiation emitted during the screening process.

Ȭ¢ȱȱ ȱ¢ȱ

Unlike traditional X-ray machines that measure the X-ray absorption pattern of different

materials, X-ray backscatter technology works by emitting a X-ray beam and measures the scatter

or reflections of the beam. The key difference is that organic materials do not absorb much of the

X-ray, allow the beam to mostly pass through, thus making traditional X-rays – which measure

absorption characteristics – a poor system for differentiating organic material. X-ray backscatter

systems, on the other hand, do a much better job of differentiating organic materials, because

different chemical elements in the material deflect these beams quite differently. This makes

backscatter a well suited technology for detecting organic explosives in either solid or liquid form

as well as drugs. The ability to provide high quality imaging of organic matter, however, raises

privacy concerns because X-ray backscatter technology can accurately image body parts normally

concealed under clothing. This has raised considerable concerns among privacy advocates, as

noted above, and it has resulted in the TSA requiring that specific privacy filters and special

operating procedures be put in place to maintain the privacy of individuals being imaged by these

systems.

The use of X-ray backscatter devices may also generate some concern over public health and

safety because these devices emit ionizing radiation, albeit in very small doses. It is estimated that

each scan exposes an individual to 10 microRems of radiation, which is about 1% of the radiation

exposure experienced every day. The system in use in testing by the TSA meets American

National Standards (ANSI) requirements and is regarded as safe for all passengers, including

small children and pregnant women.65 The X-ray backscatter technology also provides an

alternative to traditional X-ray machines for screening carry-on items, and systems are available

that use backscatter technology for inspecting carry-on items, however, the TSA’s present

initiatives to acquire and deploy advanced technology X-ray systems for carry-on screening do

American Science and Engineering (AS&E), Inc., TSA Z Backscatter Pilot. AS&E, Billerica, MA.

ȱȱȱ

řŘȱ

ȱȱǱȱȱȱ ȱȱȱ

not include X-ray backscatter solutions, relying instead on high resolution X-ray systems capable

of providing multiple image views.

ȱȱ ȱ¢ȱ

Millimeter wave screening technology refers to an array of screening devices capable of creating

high detail images of items otherwise visually concealed. These devices emit electromagnetic

waves in the 30-300 giga-Hertz (gHz) frequency range, that are capable of penetrating a variety

of items that cannot be seen through, including clothing, vehicles, and shipping containers. For

this reason, millimeter wave technologies potentially have a broad array of security applications,

including the screening of individuals, vehicles, shipping containers, baggage, or other items. The

screening devices capture the reflections of these waves as they bounce off visually concealed

items. Depending on the composition of the material, some of the energy will be reflected and

some will be absorbed. While metals and the human body tend to be highly reflective and will

appear light or white in the generated image, materials such as plastics, ceramics, and organic

materials, including organic explosives, will be partially reflective, and seen as partially

transparent in the image generated using this technology.66

The resolution of current millimeter wave imaging systems allows for a relatively high detail

image to be generated. However, like X-ray backscatter screening of individuals, images must be

generated from multiple angles or views because, as mentioned above, millimeter waves are

largely reflected by the human body and do not penetrate through the body to see items concealed

on the other side. Also, like X-ray backscatter technology, millimeter wave imaging systems can

detect concealed items, but cannot analyze the composition of those items. Therefore additional

screening techniques would be needed to determine whether a detected item contained explosive

material. According to the vendor, the millimeter wave screening technology currently being

evaluated by the TSA can scan individuals in about two seconds.67

Since the millimeter wave signals emitted by these devices are non-ionizing and are emitted at

very low power levels, health and safety concerns have not been a significant issue related with

this technology. While some still question the potential health effects of exposure to

electromagnetic energy, the TSA points out that the millimeter wave imaging systems currently

being field tested emit 10,000 times less energy than a typical cell phone transmission.68 For TSA

screeners, occupational exposure is regulated by Occupational Safety and Health Administration

regulations and standards, and exposure to the traveling public would be expected to be much

lower than these levels in most cases.69

D.M. Sheen, D. L. McMakin, H. D. Collins, T. E. Hall, & R. H. Severtsen, Concealed Explosive Detection on

Personnel Using a Wideband Holographic Millimeter-Wave Imaging System. Proceedings of SPIE—Volume 2755

Signal Processing, Sensor Fusion, and Target Recognition V, Ivan Kadar, Vibeke Libby, Editors, June 1996, pp. 503513.

L3 Communications, Active Millimeter Wave Screening.

Transportation Security Administration, Millimeter Wave.

See, especially, 29 CFR §1910.97 - Nonionizing radiation.

ȱȱȱ

řřȱ

ȱȱǱȱȱȱ ȱȱȱ

ȱ¢ȱȬ¢ȱȱ

The TSA has been using the term Advanced Technology or AT X-ray to refer to a wide range of

possible next generation X-ray screening systems to be deployed for screening carry-on items at

passenger checkpoints. The TSA has been field testing three different systems that provide a

variety of enhanced features including improved resolutions, multiple views, and automatic

explosives detection capabilities. The TSA has requested funding through FY2009 to deploy more

than 900 of these systems, primarily at Category X and Category I airports. The TSA anticipates

that it will have deployed enough of these units to provide coverage of 60% of lanes at these

larger airports by the end of FY2009. The systems cost, on average, about $200,000 each.

Category X and Category I airports are slated to be the first to get these new technologies. The

strategy reflects a view that focusing efforts on the largest airports will encompass the greatest

number of passengers and the highest risk flights. The aviation screening system in the United

States, however, operates using a single gateway concept, meaning that passengers are typically

only screened once at their originating airport. Terrorists may exploit knowledge that smaller

airports may not have the same level of advanced checkpoint technologies as larger airports to try

to minimize detection. Such concerns may prompt additional policy debate over whether focusing

on the largest airports first is the best strategy, or if targeted or accelerated deployment of these

technologies to include small and mid-sized airports could provide an alternative strategy for

minimizing such a threat.

ȱȱȱȱȱȱȱ

¢ȱȱ

A variety of other technologies are available and have been suggested as options for screening

carry-on items. For example, some vendors have developed small-footprint computed

tomography (CT) based scanners tailored for passenger checkpoint use that have throughput rates

on the order of 400 bags per hour and include automated explosives and weapons image detection

algorithms. CT-based systems are also capable of generating 3-D or multi-angle images of

scanned items for image analysis by screeners. While these systems offer some unique

advantages over AT X-ray by incorporating automated EDS detection algorithms used for

checked baggage, and allowing for the viewing of 3-D images or viewing the item from virtually

any perspective, they are considerably more expensive than available AT X-ray systems. A key

policy issue is whether the potential enhancements these technologies offer compared to AT X-ray

provides a benefit equal to or greater than the cost difference. This may be a difficult question to

answer depending on testing methods and assumptions. Findings may indicate that CT-Based

systems for passenger checkpoint screening may provide unique benefits in some instances, but at

present, the TSA appears to favor the use of AT X-ray technologies to replace current generation

X-ray systems in most, if not all, instances.

Also, the DHS Science and Technology Directorate has been working with Los Alamos National

Laboratory to develop and test ultra-low field magnetic resonance imaging (MRI) scanning

capabilities to screen for threat items. Researchers have developed a prototype system that may

eventually be integrated into checkpoint screening systems to establish a reliable liquid

explosives detection capability. The system, called SENSIT (for “sense-it”), is being designed to

identify and differentiate fluids by including a database of MRI signatures for both threat and

non-threat liquid items. Potential advantages of using ultra-low field MRI technology is that it is

ȱȱȱ

řŚȱ

ȱȱǱȱȱȱ ȱȱȱ

considered non-invasive, widely regarded as being safe for human exposure, and can potentially

be integrated with the existing airport screening checkpoint architecture.70

Millimeter wave technology, discussed above in reference to whole body imaging systems, also

has the potential of being adapted for use in screening carry-on items, although it is not clear that

this would provide any advantages over advanced technology X-ray systems. Millimeter wave

systems, however, have another potential application in covert, passive scanning of objects. For

example, patrol vehicles could potentially use millimeter wave scanning systems to inspect

vehicles standing at passenger pick-up and drop off points for suspect items, such as possible

explosive devices. In the terminal, such technology also has potential application for the remote

inspection of unattended or otherwise suspect items from a distance using, for example, robotic

sensor platform. However, such potential applications of this technology pose considerable policy

and legal questions regarding individual privacy rights and reasonable cause for search. At

present, therefore, the application of this technology in the aviation security domain appears to be

limited to consensual searches of passengers conducted at screening checkpoints.

While the major push for these new technologies is to improve both the detection capabilities and

the efficiency of the screening process for airline passengers, concerns have been raised that

airport workers that access sterile and secure areas are often exempted from screening procedures

as a matter of routine. Tests of programs for screening workers on either a mandatory or on a

random basis has raised questions over how such requirements may impact equipment and

staffing needs if implemented on a nationwide basis.

ȱȱȱ

The lack of mandatory screening for airport workers has been an issue of debate for some time.

At most airports, identification checks, along with random or targeted screening, are used in lieu

of 100% physical screening for airport workers. It has been estimated that nationwide about

600,000 such workers access secured areas of airports each day. In 2003, Representative DeFazio

expressed particular concern over these practices, noting that this lack of checkpoint screening of

airport workers creates vulnerabilities in which workers, or individuals with counterfeit or stolen

worker identification, could pass threat objects into secured airport areas or travel on aircraft

without security screening by using electronic tickets.71

The TSA and airport operators have voiced concerns that full checkpoint screening of airport

workers would be very time consuming and would significantly impact limited security screening

resources and TSA’s ability to process airline passengers through screening checkpoints.72 While

procedures vary from airport to airport, prior to 2007, only Miami International Airport had

implemented a system requiring 100% physical screening of all airport workers accessing secured

areas. However, a security incident in the spring of 2007 brought the issue to national attention.

On May 5, 2007, the TSA was alerted to possible weapons on board a Delta Airlines flight from

Orlando, Florida to San Juan, Puerto Rico after Orlando police received a tip from their

“Detecting Liquid Explosives,” Air Safety Week, November 19, 2007.

National Public Radio. “Some Members of Congress Raising Concerns about Potential Security Lapses at Airports,”

Morning Edition, May 22, 2003.

“Technical corrections bill passes out of subcommittee.” Aviation Daily, Vol. 352, No. 35, p. 3, May 19, 2003.

ȱȱȱ

řśȱ

ȱȱǱȱȱȱ ȱȱȱ

anonymous crime hotline.73 The TSA ordered that the flight be reverse-screened upon arrival in

San Juan.74 In other words, all passengers, carry-on items, and checked baggage were screened

again as the passengers disembarked in San Juan. The search unveiled 14 guns – 13

semiautomatic handguns and a .22 caliber rifle – and eight pounds of marijuana in a carry-on bag

toted by a Comair employee traveling on the flight.75 He and others accomplices, also employees

of Comair in Orlando, were able to smuggle these items onboard the airplane because their access

credentials allowed them to bypass passenger screening checkpoints. The incident highlighted the

long debated insider threat posed by airline employees that are not routinely screened before

accessing sterile and secure areas of airports.

Following the incident, the TSA ramped up employee screening and security measures.76

However, neither the TSA nor Congress has required airports to implement 100% screening of all

airport employees. As noted above, only Miami International Airport had a program in place prior

to this incident to screen 100% of airport employees accessing secured areas. Following the

incident, Orlando International Airport implemented a similar program. However, at other

airports, screening is conducted only on certain airport workers or, more typically, is done on a

random basis, if at all.

The TSA is currently testing various techniques for random and targeted screening of airport

workers accessing secured areas of airports under its Aviation Direct Access Screening Program

(ADASP). The ADASP was initiated in July 2006, and according to the TSA, the program places

an emphasis on unpredictable, random screening of airport employees, items carried by them, and

vehicles passing through airport access points. The Airports Council International - North

America (ACI-NA) asserts that the random, unpredictable nature of worker screening under the

ADASP will make it difficult for terrorists to ascertain and exploit operational patterns.77

Moreover, the TSA emphasizes that its personnel can be “surged” on very little notice to step up

airport worker screening in response to threat intelligence or other indicators of heightened risk.78

Therefore, both the TSA and the industry support the risk-based, random screening concept being

developed under the ADASP as opposed to a more costly and resource intensive effort to conduct

100% screening of airport employees, similar to what was implemented in Miami and Orlando.

As noted above, both Miami International Airport (MIA) and Orlando International Airport

(MCO) have implemented full screening programs for airport workers, requiring all those

accessing sterile and secured areas to undergo physical inspection. Additionally, a trial program at

Armen Keteyian, Pia Malbran, and Phil Hirschkorn, CBS News Investigative Unit, “14 Guns And 8 Bags Of Pot On

A Plane, Lax Security For Airport Workers Leads To Arms And Drug Smuggling,” CBS News, March 8, 2007.

Testimony of Kip Hawley, Assistant Secretary, Department of Homeland Security, Transportation Security

Administration, Before the United States House of Representatives, Committee on Homeland Security, Subcommittee

on Transportation Security and Infrastructure Protection, April 19, 2007.

Armen Keteyian, Pia Malbran, and Phil Hirschkorn, CBS News Investigative Unit, “14 Guns And 8 Bags Of Pot On

A Plane, Lax Security For Airport Workers Leads To Arms And Drug Smuggling,” CBS News, March 8, 2007.

Testimony of Kip Hawley, Assistant Secretary, Department of Homeland Security, Transportation Security

Administration, Before the United States House of Representatives, Committee on Homeland Security, Subcommittee

on Transportation Security and Infrastructure Protection, April 19, 2007.

Testimony of Greg Principato, President, Airports Council International - North America, Hearing on Aviation

Security: The Necessary Improvements to Secure America’s Airports, Before the Subcommittee on Transportation

Security and Infrastructure Protection, Committee on Homeland Security, House of Representatives, April 19, 2007.

Testimony of Kip Hawley, Assistant Secretary, Department of Homeland Security, Transportation Security

Administration, Before the United States House of Representatives, Committee on Homeland Security, Subcommittee

on Transportation Security and Infrastructure Protection, April 19, 2007.

ȱȱȱ

řŜȱ

ȱȱǱȱȱȱ ȱȱȱ

Boston Logan International Airport (BOS) requires 100% physical screening of airport workers

and vehicles accessing the airfield. While 43 TSA screeners were added to staff five airfield

checkpoints at BOS, an airport official speculated that a full-time requirement to screen all airport

workers at airport perimeter checkpoints and at designated terminal checkpoints prior to

accessing sterile area may require as many as 1,300 additional TSA screeners at BOS alone.79

However, it is important to point out that, unlike the statutory requirement for TSA screening of

passengers, no such requirement exists for airport worker screening, so this function could be

conducted by private screening vendors. In any case, system-wide implementation of 100%

airport worker physical screening may require tens of thousands of new screener personnel,

whether they be TSA screeners or private screeners.

The TSA maintains that through a layered security approach – relying on extensive background

checks, access controls, surveillance, and law enforcement presence at airports – adequate

security can be established and no specific need for 100% screening of all airport workers has

been identified. The TSA believes that stepped up random screening of workers can provide an

additional layer of security to augment these other longstanding layers of airport security.

In addition to random selection techniques, additional steps are under consideration, including the

use of behavioral profiling techniques for targeting physical inspections of airport workers.80 For

example, at several Florida airports and in San Juan, Puerto Rico, the TSA has augmented the

ADASP program with Saturation Security Teams (SSTs) that rove through sterile and secure areas

of airports using behavioral observation techniques to evaluate and select airport workers for onthe-spot random inspections.

The TSA has also been mulling the idea of creating a voluntary program, allowing certain

“certified employees” that undergo more extensive background checks to be exempt from routine,

but not random, inspections. Some familiar with airport operations observe that certain categories

of workers, such as maintenance workers, who must routinely pass into and out of sterile and

secured areas, often carrying tools, knives, and other dual-use items that could be used as a

deadly weapon. Repeatedly screening such individuals throughout the day may be labor intensive

and arguably ineffective against preventing certain kinds of weapons from being carried into

sterile and secured areas. Additional background checks and vetting of these workers may provide

an option for exempting them from routine screening every time they access sterile and secured

areas of airports.

ȱȱȱȱȱ ȱ

While the TSA has been testing various procedures for screening airport employees, it has also

moved forward to develop a system for validating the identity of airline crews as a means for

sterile area access in lieu of physical screening at security checkpoints. The 9/11 Act (P.L. 11053) required the TSA to assess the feasibility of creating a credentialing and identity verification

system to allow airline flight crews access to the sterile areas of airports, and if feasible, initiate

implementation of such system.

“New Screening Program Begins Test At Logan,” The Boston Globe, May 7, 2008.

Ibid.

ȱȱȱ

řŝȱ

ȱȱǱȱȱȱ ȱȱȱ

Since the 9/11 attacks, flight and cabin crews have been required to undergo physical screening at

airport checkpoints, largely over concerns that terrorists or criminals could gain access to secured

areas of airports or to air carrier aircraft by impersonating airline crew members, particularly

pilots. Pilots and flights attendants and organizations representing these groups have complained

that while they were required to pass through screening checkpoints whenever accessing sterile

areas of airports, other airport and airline workers have been allowed to bypass screening,

pointing out that pilots and flight attendants were subject to the same background checks as

airline workers.81 Nonetheless, the TSA had expressed specific concerns about the level of access

pilots, as well as flight attendants, had to aircraft and cockpits, fearing that an imposter dressed as

an airline crew member could gain access allowing them to sabotage or hijack an aircraft if such

an individual were allowed to bypass screening checkpoints.

Similar concerns had also been raised about allowing crew members from other airlines from

riding on the cockpit jumpseat. Prior to the 9/11 attacks, it had been a longstanding industry

practice to allow flight crew personnel from other airlines to ride in the cockpit as a means of

transportation to position pilots, and sometimes flight attendants, for their flight assignments.

Most major airlines had reciprocal agreements with the other airlines to allow for this. However,

after the 9/11 attacks, the practice was terminated because there was no industry-wide system to

authenticate the credentials of flight crews from other airlines. Airline crews were, therefore,

often required to fly standby on a space-available basis to commute to and from their flight

assignments.

As a result of an industry need to provide jumpseat access privileges on other airlines’ aircraft in

order to maintain efficient crew positioning, an industry-wide database called the Cockpit Access

Security System (CASS) was developed. It was field tested beginning in 2003 and received TSA

approval for full operational deployment in September 2005. This database is maintained by

ARINC, Inc. using human resources data provided by the individual airlines. The system provides

gate agents identity verification of flight crew members by transmitting an up-to-date photograph

and background information to compare to employee credentials using a secure Internet-based

interface.

For the sterile access area testing, the TSA has leveraged the investment in the development of

CASS. For flight crew sterile area access, called crewPASS, the system relies on secure Internet

access to the CASS database via TSA checkpoint computer terminals positioned at exit lanes to

validate the identity of airline flight crew members. The testing is being conducted at BWI,

Pittsburgh International Airport, and Columbia (S.C.) Metropolitan Airport, and it is currently

limited in participation to uniformed flight crew members. Further evaluation of the program,

including whether to extend participation to cabin crew members, is to be made based on the

results of this testing.

The TSA is continuing to study ways to further enhance airline crew identity validation, and is

assessing how this program may be able to enhance security by reducing the number of

individuals requiring physical screening, allowing screeners and behavioral detection officers to

better focus their efforts on detecting suspicious items and suspicious behaviors.82 Nonetheless,

See the Transportation Security Administration’s Screening of Airline Pilots: Sound Security Practice or Waste of

Scarce Resources, Hearing Before the Subcommittee on Economic Security, Infrastructure Protection, and

Cybersecurity of the Committee on Homeland Security, House of Representatives, One Hundred Ninth Congress, First

Session, May 13, 2005. Serial No. 109–13, U. S. Government Printing Office, Washington, DC: 2005.

See Transportation Security Administration, “TSA Announces Launch of Expedited Screening for Flight Deck Crew

(continued...)

ȱȱȱ

řŞȱ

ȱȱǱȱȱȱ ȱȱȱ

flight crew members participating in crewPASS are subject to random screening and behavioral

observation.

Additionally, in September 2008, the TSA launched a separate test of a biometrics-based access

control system for flight crews.83 The system, known as SecureScreen, is being tested on about

200 Southwest Airlines pilots based at BWI airport. The pilots participating in the testing are

being issued biometric identity cards that store fingerprint, digital photograph, and personally

identifiable security information. Card readers have been installed at TSA security checkpoints at

BWI to verify pilot identities, allowing pilots to bypass routine security screening. However,

pilots participating in the test may still be subject to random or targeted screening as a secondary

layer of security.

ȱȱ ȱ

(name redacted)

Specialist in Aviation Policy

[redacted]@crs.loc.gov, 7-....

(...continued)

Members,” Press Release, July 17, 2008.

Kathleen Hickey, “TSA Tests Biometrics for Pilots,” Government Computer News, September 18, 2008.

ȱȱȱ

řşȱ

EveryCRSReport.com

The Congressional Research Service (CRS) is a federal legislative branch agency, housed inside the

Library of Congress, charged with providing the United States Congress non-partisan advice on

issues that may come before Congress.

EveryCRSReport.com republishes CRS reports that are available to all Congressional staff. The

reports are not classified, and Members of Congress routinely make individual reports available to

the public.

Prior to our republication, we redacted names, phone numbers and email addresses of analysts

who produced the reports. We also added this page to the report. We have not intentionally made

any other changes to any report published on EveryCRSReport.com.

CRS reports, as a work of the United States government, are not subject to copyright protection in

the United States. Any CRS report may be reproduced and distributed in its entirety without

permission from CRS. However, as a CRS report may include copyrighted images or material from a

third party, you may need to obtain permission of the copyright holder if you wish to copy or

otherwise use copyrighted material.

Information in a CRS report should not be relied upon for purposes other than public

understanding of information that has been provided by CRS to members of Congress in

connection with CRS' institutional role.

EveryCRSReport.com is not a government website and is not affiliated with CRS. We do not claim

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.