Passenger Screening Technologies
Perceptions of increased threats from explosives and nonmetallic weapons have prompted the investigation of new passenger screening technologies, including chemical trace-detection techniques and imaging methods that can see through clothing. The development of these technologies has reached the stage at which operational implementation can be contemplated. However, possible negative public reaction toward many of these new detection technologies will have to be addressed before these systems can be used in airports. Demands for additional space, utilities, labor costs, and increased operator skills that these technologies could impose on air carriers and airports also will have to be considered. This chapter describes the technological aspects of the systems under consideration.
Screening procedures currently used in U.S. airports, at least during routine operations, involve metal-detection portals for screening passengers and x-ray imaging systems for screening hand-carried baggage. Metal-detection devices impose a time-varying magnetic field in the space within the portal that induces eddy currents in metallic or ferromagnetic objects passing through that space. Various methods are used to detect these eddy currents, and when they exceed a preset level, an operator intervenes to ascertain the presence or absence of a dangerous object or weapon. The effectiveness of this security screening system depends not only on the performance of the equipment, but also on the performance of the personnel operating the equipment and resolving the alarms.
The detection instrumentation can be adjusted to optimize its ability to detect specific metals or alloys. The FAA utilizes a number of specific weapons to test the proper operation and performance of these metal-detection units. Typically, instruments are tuned for the optimum detection of these FAA test objects, at the expense of reducing instrument sensitivity in detecting weapons or objects not contained in this set of specific test weapons.
The FAA is considering for future application several new technologies capable of detecting a wider range of threat objects. The following section describes an approach used by a foreign air carrier, followed by sections describing the new technologies being considered by the FAA.
PASSENGER-PROFILING SYSTEM
Among the presentations to the panel was a particularly enlightening one by Dan Issacharoff, the former head of security for El Al Airlines of Israel. Because of its national affiliation, El Al has frequently been a terrorist target. In response, El Al has developed an extensive security program requiring inspection of all baggage and the face-to-face questioning of all passengers. Issacharoff said the El Al security system emphasizes the identification of people who could be a threat, rather than the detection of objects that could be used to hijack or destroy an airplane. The system used to identify people who could be a threat is illustrated in figure 3-1, which identifies five types of people who could pose a threat to an airplane. ranging from naive terrorists, passengers who are unaware that they are carrying dangerous objects, to suicide terrorists who intentionally carry dangerous objects to destroy the airplane and kill everyone on board, including themselves. El Al has also developed psychological profiles of these individuals and a passenger-interrogation technique designed to identify them during check-in and before boarding.
This system has worked well for El Al, but Issacharoff pointed out that El Al flies out of approximately 200 airports worldwide. In contrast, U.S. air carriers operate more flights out of more than 400 airports in the United States alone. In addition, a large number of El Al passengers travel on international flights and arrive at the airport early enough to allow time for security screening. The time- and personnel-intensive system used by Ei Al may be suitable for international flights, but it would be inappropriate for an operation the size