DEVELOPMENT OF AVIATION SECURITY
Two major events caused the public to exert pressure on the U.S. government to implement security procedures at airports and to mandate security requirements for U.S. air carriers. The first was the increase in the incidence of hijackings during the late 1960s and early 1970s (see figure 1-1), which resulted in the establishment of Anti-Hijacking Program of the Federal Aviation Administration (FAA). The second event was the destruction of Pan American Airlines Flight 103 over Lockerbie, Scotland, on December 21, 1988, which resulted in the creation of the President's Commission on Airline Security and Terrorism in 1989 and the enactment of the recommendations of that commission into the Aviation Security Improvement Act of 1990 (Public Law 101-604).
FAA Anti-Hijacking Program
On September 11, 1970, President Richard Nixon announced "a program to deal with airplane hijacking," which ordered air carriers to deploy "surveillance equipment and techniques to all appropriate airports in the United States." The president further instructed the Departments of Defense and Transportation to work with the U.S. air carrier industry to determine if metal detectors and x-ray devices used by the military could assist in preventing hijackings. On February 1, 1972, the FAA issued a rule requiring air carriers to use a screening system, acceptable to the FAA, that would require screening all passengers "by one or more of the following systems: behavioral profile, magnetometer, identification check, physical search." Hijackings continued and on December 5, 1972, the FAA issued emergency rules that required screening all passengers and carry-on baggage on all certified, scheduled passenger aircraft. The anti-hijacking or screening program currently used by U.S. air carriers is almost identical to the program initiated in 1972. This program requires air carriers to implement a security program capable of preventing the introduction of weapons and explosive or incendiary devices aboard an aircraft. Since the issuance of this rule, the screening program has been improved in terms of training procedures, x-ray and metal-detector standards, access control specifications, employment standards, and testing requirements.
As a result of the increased incidence of hijacking and sabotage of U.S. air carriers in the past quarter century, numerous statutes, treaties, and regulations have been promulgated by a variety of entities to establish the current U.S. civil aviation security system (see appendix A). Air carriers, airports, and the FAA each have specific roles to play in ensuring airport security, as outlined in table 1-1.
Approximately 1.5 million commercial aviation passengers are screened in the United States each day for weapons and dangerous articles prior to boarding an airplane. Passengers place their carry-on baggage on a conveyor belt for inspection by x-ray equipment, and they walk through a portal that detects the presence of metallic objects. If the metal-detecting portal sounds an alarm, passengers are searched further to determine the cause of the alarm and to ensure that they are not carrying objects that could be a threat to aviation security. These alarm-clearing search procedures employ either a hand-wand metal detector or a physical pat-down search. The technologies for detecting metallic objects are mature, and the manner in which these technologies are implemented to ensure airport and air carrier security is familiar to travelers.
However, these technologies are not capable of detecting nonmetallic weapons, plastic explosives, and other dangerous materials. The FAA is working to make current technologies more effective and to develop new technologies with wider applicability. As these new technologies mature, issues regarding their implementation in airports, including passenger acceptance and air carrier and airport accommodation, will become important factors in determining which technologies will be appropriate for airport use.
The Panel on Passenger Screening investigated a variety of nontechnology issues related to the implementation of new screening technologies to assist the FAA in identifying the most promising technologies. The panel reviewed potential screening devices or methods currently under consideration by the FAA for use in airports. The panel also assessed aspects of each method that could cause public concern over such issues as health risks involved (e.g., exposure to radiation), privacy, and traveler comfort, in light of current and
anticipated health regulations, and privacy laws. The panel considered ways in which the methods could be implemented to maintain high levels of effectiveness, while minimizing health risks and increasing public acceptance. The panel also identified key factors that could affect their implementation, considering mitigating strategies and alternate screening methods for those passengers who wish to avoid the automated system. Methods for clearing alarms also were discussed.
Because both current and new technologies require security personnel to supplement the automated system when a passenger sets off the alarm, the panel considered the operator as an integral part of the entire passenger screening system.
TABLE 1-1 Responsibilities of Air Carriers, Airport Operators, and the FAA for Passenger Screening
Provide secure travel
Maintain security program
Provide secure operating environment
Maintain security program
Provide administrative and procedural guidance
Coordinate crisis situations
Provide technical assistance
Fund carrier/airport security via travel purchase
Sources: ATA (n.d.); ATA (1984); FAA (1975); FAA (1981); 14 C.F.R. §107.20 (1995); United States v. Davis (1973).
The FAA integrates information from the intelligence community, policymakers, air carriers, and airports to determine the level of threat to civil aviation. When no specific threat has been identified, the security system operates at a basic level for detecting weapons and explosives on passengers or in their baggage. Low alert levels1 indicate that the FAA considers the probability of an attempted bombing or hijacking to be minimal. If specific hijacking or terrorist targets have been identified, the FAA declares a higher alert level and warns air carriers and airport authorities of the specific bomb or hijacking threats and of their potential locations. For higher alert levels, the security-screening process imposes additional procedures to increase the likelihood of detecting the terrorist. Rapidly changing situations may require significant modifications in screening procedures, with little or no advanced warning. These procedures involve more thorough screening, including additional baggage inspection, passenger questioning, and identification checks.
The level of tolerance demonstrated by the traveling public for the inconvenience, lack of privacy, perceived health risks, and delays for passengers, greeters, and air crews will be
proportional to their perception of the severity of the threat. More expensive screening equipment and more intrusive screening procedures will be acceptable at higher alert levels, but only if the threat is perceived to warrant them and if the equipment or procedures are perceived to be effective in deterring the threat. The dilemma in passenger screening is how to provide an effective and suitable level of screening at a reasonable cost for all threat levels.
The performance of a security system must be evaluated to determine both its effectiveness and suitability. Effectiveness is the capability to detect threat objects, and it is generally dependent on the capabilities of the system technology. Suitability is the capability of the system to operate with few undesirable characteristics (e.g., elevated radiation levels). Performance should be evaluated continually, and the process should be designed to provide feedback to allow air carriers and equipment manufacturers to improve the effectiveness and suitability of a system.
Compliance with standards set by the FAA is considered the minimum acceptable level of performance. For example, when metal-detection portals are first installed in an airport or moved to a new location, they must be proven to perform at the minimum compliance level specified by the FAA. Screening systems are evaluated for both equipment and system compliance to ensure a minimum level of performance. Evaluation includes testing the ability of the system to detect, react to, and properly respond to a terrorist threat or action. For example, system compliance may be determined by using government red teams to test airport systems, as
1 The FAA has defined specific aviation security (AVSEC) alert levels and the circumstances justifying the declaration of higher alert levels. These definitions are considered sensitive information. The descriptions used here are generally illustrative of the FAA alert levels.
described to the panel by a former head of security for El Al Airlines (Issacharoff, 1995). The Panel on Passenger Screening concentrated on the suitability of new technologies and paid particular attention to the interrelationship between suitability and effectiveness.
Current passenger security-screening requirements were established as a result of the pre-1972 increase in the number of hijackings. These requirements focus on the ability to find passengers carrying metallic weapons that may be used to intimidate the air crew into changing the destination of an aircraft. However, with increasing international political unrest and the attractiveness of U.S. aircraft as terrorist targets, the FAA has recognized the need to expand airport security-screening processes to include the detection of plastic explosives and other threat objects or substances. This need is the driving force behind the development of new screening technologies.
A number of issues are associated with the suitability and effectiveness of new airport passenger screening technologies. A main issue, which relates to suitability, is reliability, i.e., the consistency of the performance of the system. A second issue, related to effectiveness, is fidelity, i.e., how accurately the output from the system represents the item being examined. A system with high fidelity provides sufficiently detailed and accurate information to enable the operator to make correct judgments and appropriate decisions regarding the presence of objects the system is designed to detect. Low reliability or fidelity levels result in poor system performance, including false alarms and the failure to detect harmful objects.
In addition to the technological aspects of passenger screening systems, there are also reliability issues associated with the operating personnel. Sound operator judgment and decision-making capabilities are critical to successful passenger screening. Operator inaccuracies and inconsistencies can also result in the failure of a system to detect harmful objects and in false alarms, which translate into unacceptable system performance. Personnel requirements are typically addressed through selection2 and training.
Whether or not a new screening technology will be acceptable to the public is a question that involves a number of significant issues. It should be noted that the term public does not refer to a homogeneous group. Although in this report the panel refers to the typical person being screened as a passenger, the population exposed to screening is actually broader. It includes air passengers, friends and relatives of passengers, flight crews, and airport employees. Some people are exposed to screening quite infrequently, while others, who often travel by air, are screened more frequently. People exposed to screening technologies can be expected to express concerns in four areas:
· healthtypified by perceived health risks associated with exposure to x-rays
· convenienceusually a matter of delays; as delays become longer, public acceptance of a particular screening procedure decreases
· privacyfor both an individual's body and possessions; technologies that display images of the body or that involve person-to-person contact raise potential concerns about privacy
· comfortthe physical intrusion of the screening equipment on the passenger
Because people differ in terms of the importance they place on the various concerns discussed above, they will also differ in their level of acceptance or rejection of passenger screening technologies. Issues of health, convenience, and privacy are important, but the distribution of public response to these issues is equally important. Aside from considering the types of reactions new screening technologies may elicit, the FAA will have to define acceptable levels of opposition. That is, a certain proportion of the public will oppose the implementation of any new technology, and the FAA will
2 Selection involves identifying people capable of functioning, or of being trained to function, as operators at an acceptable level.
have to weigh the need for more effective airport security against the known opposition before mandating implementation of a new technology.
Widespread acceptance of a new screening technology is not simply a matter of how people respond or what percentage of the population accepts or rejects the procedure. Rather, acceptance can be viewed properly as a trade-off by the public; that is, each person will perform a personal costs-benefits analysis between the perceived threat and the benefits of a higher level of security screening. Thus, the extent to which a screening procedure is viewed as successful in providing security and the degree to which security is seen as a necessity are important factors in public acceptance.
A final point to be noted concerns the matter of choice. Where more than one screening technology is available at a particular screening point, people who object to a primary procedure, such as a technique that displays an image of the human body under clothing, may be given the option of a secondary procedure, such as searching with a hand-wand device. Although making such options available may be costly in terms of money and efficiency, doing so will alleviate many concerns. Screening technologies provide security by detecting objects, but they also function as deterrents. Their effectiveness as deterrents depends on perceived, rather than actual, reliability and fidelity.
In gathering data for this report, the panel assumed that each screening technology, at a basic level, performed the job it was designed to do. That is, the panel did not address the technical issues related to improving hardware technologies. Instead, the panel focused on the broader issues of passenger and airport or air carrier concerns that could arise with the implementation of new technologies. In the report, the panel notes instances where addressing a specific concern would decrease the effectiveness of a technology.
The panel also assumed that the technology under consideration will be used as the primary passenger screening technology or one through which all passengers will be examined. However, if the FAA and the air carriers can develop a reliable method for determining which passengers pose no danger to the flight, for example, by developing an effective passenger-profiling system, then new technologies may be used as a secondary screening system for more intensive inspection of passengers who cannot be cleared in advance. Thus, development of a passenger-profiling system holds great promise.
This report addresses three general categories of passenger screening technologies: imaging technologies, trace-detection technologies, and nonimaging electromagnetic technologies. Chapter 2 summarizes the methodology the panel used to evaluate the concerns associated with new technologies. Chapter 3 addresses the individual technology types in greater depth. Chapter 4 outlines the operating conditions under which new passenger screening technologies will have to operate. Chapter 5 discusses the role of human operators in security systems and how that role could change to improve total system performance. The final chapters, 6, 7, and 8, discuss the primary concerns (i.e., health effects, privacy concerns, and public acceptance) associated with new technologies. The panel's conclusions and recommendations are presented in chapter 9.