Forensic science in airport security

DEFINITION: All legal measures, law-enforcement activities, regulations, and forensic science applications needed to maintain the safety and security of passengers and operational facilities—including aircraft, terminals, and transportation facilities—associated with airline commerce.

SIGNIFICANCE: As rates of world travel have increased and the threat of international terrorism has grown, airport security measures have evolved to keep pace. Forensic science has contributed a number of technologies and methodologies to the effort to keep airports safe.

Airport security measures have been in place since commercial airline traffic began in the 1920s. Initial measures included the establishment of rules for luggage, boarding, and other aspects of air travel intended to provide safe passage. As the volume and complexity of air traffic increased, so did the emphasis on rules and regulations governing air passengers, aircraft, and airport security. The most basic of these took the form of regulations regarding the movement of passengers and their baggage within airports and their access to airport facilities, airplanes, and the flight tarmac.

As airports grew larger and volumes of freight and passenger traffic increased during and following World War II, the movements of passengers within airport terminals and their access to the operational infrastructure of air terminals were further restricted. Luggage restrictions and weight restrictions became routine, as did requirements concerning passenger identification and boarding passes, but these rules were established to protect passengers from harm and to ensure airport efficiency rather than as deterrents to perceived threats.

The first important changes in airport security followed several incidents in the 1950s in which bombs were planted on aircraft to destroy them in flight for insurance purposes. These were followed by additional security measures taken in the 1960s in response to a number of high-profile hijackings, some of which led to the destruction of aircraft and crews as well as passenger injuries and deaths. Airlines, agencies, and various governments around the world, including that of the United States, took the extraordinary measure of instituting a program of sky marshals to fly on board aircraft. Sky marshals were armed and charged with identifying and arresting potential menaces as well as preventing incidents during flight.

Although the sky marshal program was well conceived and well designed for that time, it never received adequate funding to place marshals on every airplane. Hijackings continued to occur, necessitating additional airport security programs. In response, the US Federal Aviation Administration (FAA) required that all passengers and their luggage be thoroughly screened beginning in January 1973. The airlines contracted this work to private security companies that supplied equipment and trained personnel. The airlines maintained operational control over their airport and aircraft facilities, and the private security companies controlled the screening of carry-on baggage at designated checkpoints prior to passenger entry to the airport waiting rooms, all under the general oversight of FAA officials.

The terrorist attacks on the World Trade Center in New York City and on the Pentagon on September 11, 2001, precipitated immediate and drastic changes in airport security matters that have remained in place. Immediately following the attacks, the federal government mandated that the highest-priority emphasis be placed on the safety and security of passengers, airport facilities, and aircraft at all airports in the United States and most around the world as well. Dramatically increased levels of security were initially reflected in the presence of armed security guards, uniformed local police officers, and even National Guard and active-duty military personnel in some terminals. The military presence was discontinued after a few months; although some passengers were comforted by the open display of weapons, others expressed alarm.

Post-9/11 Airport Security

Long-term airport security measures that remain in place since the changes brought about after 9/11 include dramatically increased scrutiny of passengers and their carry-on luggage. This has led to the implementation of a number of measures aimed at passenger behavior. First, people are no longer permitted to leave cars unoccupied at terminals or to leave luggage unattended. Passengers must wait in long lines in which they and their luggage are checked with scanners, metal detectors, and, in some cases, substance-detection dogs. Each individual must present some form of personal identification with a photograph, such as a driver’s license or passport, and must agree to extensive searching of luggage. These strictures sometimes lead to long waiting times and travel delays, all of which have been sanctioned by federal authorities; most such measures have met with general passenger approval.

Behind-the-scenes changes in airport security have been equally dramatic. Each airport, similar to a small town, now has a dedicated police force hired specifically to maintain airport security. Depending on the locality, the airport force may be a private policing agency or a part of the local police force with a police station maintained at the airport. Most airport police forces also include dogs that have been trained to detect explosives and drugs.

Airports have tested and purchased a number of technologically advanced and very expensive apparatuses that permit rapid scanning of baggage and passengers. These include X-ray backscatter scanners that can detect hidden weapons and explosives on passengers, as well as automated explosive detection system (EDS) machines that are able to scan hundreds of pieces of luggage per hour. New and improved computed axial tomography (CAT) scanners have been developed that provide three-dimensional images, thereby more effectively detailing luggage contents; this advancement promotes rapid and accurate identification of hidden weapons, bombs, and packets of chemicals. In 2022, one thousand millimeter wave-based advanced imaging technology (AIT) scanners had been installed at US airports. AIT scanners, which require passengers to stand inside them with their hands up while they are scanned, have improved airport security. However, experts noted that AIT hardware is more than a decade old and is in need of updating.

Forensic Applications in Airport Security

Airlines and airline facilities must be protected from all forms of terrorism, including bombs planted in luggage, airplane hijackers, and attacks using chemical or biological weapons. Since September 11, 2001, the US government has poured millions of dollars per year into improving airport security, but security breaches still occur. For the most part, these involve identity fraud, drug trafficking, possession of explosives or weapons, or possession of international contraband, harmful chemicals, or biotoxins. Forensic science plays an important role in the prevention and investigation of such security breaches.

The first line of defense against terrorist threats to airport security involves a system of enclosure and screening that prevents access to aircraft and tarmacs. All airports in the United States are surrounded by tall fences or walls, making it nearly impossible for anyone to sneak in. In addition to constant video surveillance throughout airports, security personnel watch every checkpoint, entry, and exit. Upon entrance, both people and luggage pass through metal detectors. Luggage is also exposed to X-rays and may be searched. Individuals are also required to agree to noninvasive searches if asked to do so. Any person who is deemed a threat is subject to more intensive searches.

Modern airport security measures also involve more clandestine operations, such as profiling and the comparison of passenger names and identifications against lists of known terrorists. Airport security profiling involves generalizations about the personality types and physical characteristics of people who may pose threats to other passengers. Security personnel are urged to be on the lookout for particular “types.” Therefore, while random baggage and clothing checks are conducted, owing to the nature of many international terrorist attacks, ethnic profiling may also occur. Passengers on flights into the United States from overseas are also subject to profiling and comparison against terrorist “watch lists.” If it is discovered that the passenger list of an inbound aircraft includes a known or suspected terrorist, the plane may be turned back, diverted to land at a designated high-security airport, or refused landing permission anywhere in the United States.

Anyone found to be carrying a weapon in an airport is immediately apprehended and the weapon removed. Forensic scientists then confirm and attest in court that the object was cause for the subject’s arrest. In the case of gun possession, firearms analyses are performed in a laboratory to determine the model of the weapon and to recover the serial numbers if removed.

Hidden explosives may be detected using modern explosive detectors that use chromatography to detect volatile gases given off by explosive mixtures. Drug-detection and bomb-sniffing dogs are led by specialized teams at customs checkpoints and can often be seen roaming common rooms in airports as well. If a suitcase or other device is suspected of containing harmful material, it is often further tested with a mechanical “chemical sniffer.” If hazardous material is found, be it illegal drugs, explosive material, chemicals, or other toxins, the individual is apprehended and held until forensic scientists can conduct toxicological and chemical composition tests to determine the identity of the substance. If the substance is determined to be an illicit one, the individual is further detained to face charges of possession of an illegal substance.

The detection of possible biological weapons is much more difficult than the detection of other kinds of harmful substances. However, if airport security authorities are concerned, they can seize any suspicious substance and submit it for forensic analysis to determine what it is. Unfortunately, no standard procedure yet exists among airline or FAA officials for dealing with possible biological weapons.

A valid driver’s license is sufficient identification for a person flying within the United States; a passport is needed to fly internationally. Both of these forms of identification, however, provide merely photographs and some additional personal information about the appearance, age, and residence of the individual. The future of individual identification with respect to airport security is likely to involve screening systems based on biometrics—that is, human recognition based on physical traits such as fingerprints. Biometric identification systems include fingerprint scanning, iris and retina scanning, and facial recognition technologies. In some cases, handwriting and voice recognition are also used to confirm identities.

Among the airport security measures that have been put in place in the United States since September 11, 2001, those involving biometric technologies have become particularly controversial. Some feel comforted by the prospect of being identified by their own fingerprints or retinal images, whereas others feel that these methods of identification are invasive and violate personal privacy. Also, many fear the damage that could be done if hackers or identity thieves gain access to the databases in which biometric data is stored.

According to an article in Security Magazine in 2022, future improvements in forensic science for airport security included technology that could detect smaller items. Improved imaging would offer greater detail and eliminate the need to remove footware. Experts planned to develop artificial intelligence (AI) that was able to detect threats such as 3D-printed weapons and plastic explosives, which were able to evade current technologies.

Above all other matters related to airport security, Americans are often frustrated with the long lines, personal questions, baggage and clothing searches, and other time-consuming measures they are subject to when they fly. Many believe, however, that these inconveniences are a small price to pay for increased passenger safety. With increasing technological capabilities, the US Department of Homeland Security and the Department of Defense are working on measures to expedite the security process while ensuring efficiency, effectiveness, and accurate personal identification. The next decision that Americans who fly commercially will probably have to make is whether they would rather put up with the waiting and frustration or have their fingerprints and retinal scans stored in government databases.

Bibliography

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Frain, Bill. "The Evolution of Airport Security and the Threats That Drive It." Security Magazine, 16 Sept. 2022, www.securitymagazine.com/articles/98346-the-evolution-of-airport-security-and-the-threats-that-drive-it. Accessed 16 Aug. 2024.

Haines, Stephanie. "Criminal Gangs May Be Exploiting Airport Security Gaps: Report." NewsNation, 6 Oct. 2023, www.newsnationnow.com/travel/criminal-gangs-may-be-exploiting-airport-security-gaps-report. Accessed 14 Aug. 2024.

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University of Surrey. "Researchers Reveal Ultra-Fast Bomb Detection Method That Could Upgrade Airport Security." Lab Manager, 2 Sept. 2019, www.labmanager.com/researchers-reveal-ultra-fast-bomb-detection-method-that-could-upgrade-airport-security-1101. Accessed 14 Aug. 2024.

Wilkinson, Paul, and Brian M. Jenkins, eds. Aviation Terrorism and Security. Portland, Oreg.: Frank Cass, 1999.