Encyclopedia of Security and Emergency Management

Living Edition
| Editors: Lauren R. Shapiro, Marie-Helen Maras

Airport Security: Procedures in Secured Areas for TSA and Private Security

  • Heather A. PanterEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-69891-5_2-1


Airport security TSA Security screening 


This entry explores security procedures in secured areas of airports and how governmental and private sectors intersect. Procedures in airport security have to address threats in public/nonpublic areas, in perimeter airfield locations, and within terminals. Often the private sector, with governmental oversight, screens passengers, employees, baggage, and cargo in both secured and non-secured areas of the airport. Therefore, this entry will examine how both governmental and private security sectors regulate SIDA badge areas, credentialing systems, airport access control, airfield patrol functions, and perimeter security in secure areas of airports.


Pre 9/11, private industry fulfilled a more substantial role in commercial transport security as airlines and airports relied solely upon private security contracts. Two months after 9/11, Congress enacted the Aviation and Transportation Security Act (ATSA), Public Law 107-71. This created the Transportation Security Administration (TSA), which federalized commercial passenger and baggage screening. Further, ATSA mandated that 100% of checked passenger baggage was screened (US Congress 2001). With new federalized regulations, private passenger screeners were hired, trained, and employed by the TSA, which became part of the Department of Homeland Security (Price and Forrest 2016). After the passage of ATSA, federal workers replaced contracted private security screeners in 450 commercial airports nationally, and the number of screeners went from 12,000 to over 40,000 in 1 year (Price 2018). Notably, ATSA outlined that TSA’s primary function is to ensure regulatory compliance with airport and airline security regulations, to screen passengers, to screen bags, and to deter individuals from committing unlawful acts of interference with aviation (Price and Forrest 2016). DHS’s other primary responsibilities also include information analysis and infrastructure protection; chemical, biological, radiological, nuclear (CBRN), and related countermeasures; border and transportation security; emergency preparedness and response; and coordination with other parts of the federal government, with state and local governments, and with the private sector (TSA 2006).

With augmented federalization of airport security, this lead to an altered reliance upon support from private sectors. This reliance shifted from private security agencies being responsible for most secured areas of airports to a radical shift of a blended integration with federalized agencies in security-related research and support. Currently, private sectors aid federalized security in passenger screening, personnel screening, airport access control, credentialing systems, perimeter monitoring, intelligence collection, alarm response, and detection technologies (Price 2018). This integrated merger lead to a layered intersectional approach to airport security procedures.

Presently, security procedures in airports involve the incorporation of shared responsibilities between airport operators, air carriers, private security agencies, local police jurisdictions, federal police jurisdictions, and the Transportation Security Administration (TSA). This layered approach involves distinct security procedures that occur in both unsecured (non-sterile) and secured (sterile) areas within international airports (refer to Fig. 1). Within this layered approach, there are different security threats that are addressed differently, namely, internal threats and external threats. Internally, personnel are concerns within sterile areas. Externally, criminal acts and acts of terrorism are strategic security concerns in sterile areas. As such, there are various components of airport security in sterile areas. This includes screening of passengers and carry-on luggage for weapons and explosives, screening of checked baggage and cargo for explosives, controlling access to sterile areas, clearing and badging personnel with access to both SIDA and AOA areas, and oversight of FAA inspections. Drawing upon tactics used in sterile areas (controlled by security regulating bodies), this entry examines how these current procedures uphold security in sterile areas.
Fig. 1

Diagram shows secured divisions of typical commercial airport. (Taken from Rabkin et al. (2004))

SIDA (Security Identification Display Area) and Air Operation Area Restrictions

Before examining how security layering works in international airports, the first step in understanding airport security is to identify and distinguish non-sterile and sterile boundaries within an airport. A sterile area of the airport is an area that allows passenger access to boarding aircraft, and access is controlled by TSA or an aircraft operator under 49 CFR 1544 or 49 CFR 1546 if a foreign air carrier (Price and Forrest 2016). The purpose of a sterile area located prior to boarding aircraft is to provide a passenger containment area which prevents persons from gaining access to weapons or contraband after passing through security checkpoint screening (TSA 2006).

FFA regulation Part 107, Section 205, outlines how Security Identification Display Areas (SIDA) are distinguished and regulated within sterile areas. Further, FFA regulation 107.205 authorizes airport operators to carry out measures to prevent unauthorized presence and movement in SIDA locations, establish a personnel identification system, subject each individual to employment history verifications before authorizing unescorted access to SIDA areas, and train each individual before granting unescorted access to SIDA locations. Under Title 49 CFR Part 1542, airport security policies and regulations further regulate (a) access to secured areas and sterile areas of the airport, (b) the requirement that airport personnel wear an approved access/identification badge, (c) the requirement that airport personnel challenge individuals who are not wearing the proper badge (or any badge) in security areas, and (d) the requirement that individuals maintain a proper escort of other individuals who do not have access/ID in a security area.

Monitoring of Employee Movement Through SIDA/AOA Areas

It is often a false conception that all airport employees undergo security screening before entering a sterile area (see Price 2018). Many airport workers in the United States are not subjected the same screening process as airline passengers, but instead they undergo background and criminal history checks, are issued SIDA/AOA badges, and use access-controlled doors to enter sterile areas (see 49 CFR 1542.207), where a credential check is needed. SIDA/AOA badges identify and document when workers enter/exit SIDA sterile areas in airports. Currently, American airports have debated whether all SIDA/AOA badge holders should go through the passenger screening process. As such, some airports have established screening checkpoints at airfield access gates, but private contractors working for the airport conduct employee screening, not the TSA (Price and Forrest 2016). As such, an employee’s job responsibility determines their level of access authority and their level of access through access-controlled doors or physical access control systems (PACS). PACS can include locks on a keyed door, keypad locks on doors to more advanced computerized systems with integrated closed-circuit television (CCTV) with alarmed access points (Price 2018). Most of these systems are proprieties of private companies, which develop both hardware and software to manage employee access with federal oversight (Price 2018).

Functionally, only one employee at a time can use the said doors, and SIDA/AOA badges are used as encoded keys that either restrict or permit employees to pass through regulated doors. For example, emergency personnel have access (if SIDA/AOA verified) to all areas contained within sterile areas. This includes SIDA locations and Air Operations Areas (AOA), which are any location where planes land, take off, or surface manoeuver (i.e., runways, taxiways, and aprons). Yet, other members of staff who clean planes or work in catering areas may only have access to certain portions of SIDA or AOA (see Fig. 2). For some, i.e., emergency personnel with SIDA/AOA access, emergencies often supersede screening from a regulatory perspective. Yet, regulated airport access-controlled doors prevent unauthorized personnel from entering sterile areas without undergoing screening even with SIDA badge access.
Fig. 2

Security requirements in a typical commercial airport. (Adapted from Rabkin et al. (2004))

By controlling who has access to which area, there is an extra security barrier in these sterile areas to reduce internal threats. Examples of internal threats within the sterile area would include the transportation of narcotics, bombing access, and burglary/larceny access to passenger areas and airplanes. By requiring a criminal background check to obtain a secured area ID, airports are arguably reducing the probability of criminality in secured areas. For example, if a prospective employee has an identified criminal history of theft, then the SIDA process can reduce the probability of granting them access to a tempting area for theft (i.e., non-CCTV areas where baggage is stored, duty-free items, alcohol, etc.).

Screening Technology Used Prior to Entering Sterile Areas

There are four major screening areas before admittance into any sterile areas of the airport: passengers, carry-on baggage, hold baggage, and cargo. In respect to passenger screening, Enders, Sandler, and Cauley’s (1990) evidence-based research over the effects of metal detector screening in airports found that they reduce incidents of aerial hijacking. Gabbidon et al. (2012) further found that the usage of x-ray technologies has effectively led to a dramatic decrease in the number of aircraft hijackings. Lum et al. (2006) found that when examining security, target-hardening strategies at airports through increased detection are an effective type of intervention. Constantly evolving, these target-hardening strategies (e.g., metal detectors, airport screening, whole-body imaging, etc.) have evolved since the height of airline skyjackings since 1961.

Prior to 1972, private security officers contracted through airports and airlines performed hand searches for baggage brought aboard airplanes (Wetter 2013). With the increase in air traffic and the number of air passengers, efficiency demands changed. With the invention and adaptation of x-ray imaging of baggage during security screening, later developments of imaging technologies, more sophisticated training, and certification for x-ray screeners in airport security checkpoints screening became more accurate.

Other detailed methods of baggage screening incorporate Explosive Detection System (EDS) and Explosive Trace Device (ETD) technologies to detect explosives (McLay et al. 2009). Currently, EDS, first employed in the United States in 2002, incorporates tomography that simplifies the detection of risky items (i.e., explosives) by generating topographic images (“slices”) from images taken from the interior of baggage (McLay et al. 2009). Similar to computer-aided smart x-ray, tomography employs a warning system to alert security personnel to any potential problem area located within baggage. ETD, on the other hand, is used to detect whether there are explosives in baggage by way of chemical analysis (Ergün et al. 2017).

In respect to the screening of passengers beyond metal detection processes, the security industry has developed two major types of body security scanners: one that relies upon ionizing radiation (x-rays) or non-ionized radiation (terahertz and millimeter waves) (Wetter 2013). Non-ionizing radiation has less resolution than ionized radiation, and x-rays can be absorbed by water on the body (e.g., sweating) (Wetter 2013). Notably, screening with ionizing radiation allows for higher resolution as well as the identification of objects on the body. Obviously, this has led to privacy issues regarding their usage (see Panter 2013). In the Unite States, these scanners are routinely used, yet in the worldwide security, scanners are not an approved means for screening passengers yet due to various privacy issues.

Process of Passenger Checkpoint Screening

Preliminary screening of passengers prior to a flight occurs when the initial flight is booked. Passenger names are checked against “no-fly” and selectee lists. Passenger names are checked again a “no-fly” list maintained by the Terrorist Screening Center within the FBI which contains information about known or suspected terrorists through the program Secure Flight. Due to the secrecy surrounding the criteria for inclusion on the lists, a passenger on the “no-fly” list will be able to purchase a ticket but will be unable to print a boarding pass. When the individual checks in for their boarding pass at the airport, they are notified in person that they are not allowed to fly (Ergün et al. 2017). Currently, it is unknown how many individuals are actually on “no-fly” lists.

Other individuals who book a ticket maybe allowed to fly, but they are unknowingly on selectee lists. This Secondary Security Screening Selectee (SSSS) security measure begins when the letters “SSSS” or “*S*” are printed on a selectee’s boarding pass. Prior to individual screening, this notifies TSA during a Travel Document Check (TDC) that a person must go through a more intensive screening process or they may be denied boarding in general. Just like the selection criteria for “no-fly” lists, it is unknown what the selection criteria for a selectee entail. Notably, during a Travel Document Check (TDC), TSA inspects and compares passenger identification against boarding passes for all individuals in screening lines. The TDC security process does not check for wanted felons, as TSA’s primary objective is to prevent acts of air terrorism.

During TSA screening, if a passenger is not on a “no-fly” or “selectee” list, security screening is conducted to identify if any prohibited item is located in passengers’ baggage or whether airport personnel have such substances when they are in sterile areas of an airport (Salter 2007). Therefore, in airport security procedures, hand searches are required, as well as the use of various technical devices to maintain comfort and speed of service. Security systems technology is used to screen three key elements: passengers, checked baggage, and carry-on baggage.

In passenger screening areas, physical barriers funnel passengers to a security official who conduct document verification to confirm the seat allocation/ticket matches both the passenger ID and documentation. From there, passengers place carry-on baggage into x-ray screening where contraband is detected. If any irregularities are detected in a passenger’s carry-on, the baggage goes through additional screening either manually or through ETD search until the suspected prohibited item is located. During this process, the passenger is not allowed to touch the bag in question. Passenger screening is similar with the usage of different technologies. Passengers walk through either a metal detector or whole-body imaging technology. If any irregularities are detected, the passenger goes through additional screening through a hand-wand or pat-down search.

As such, criminals with passenger tickets (who are not on “no-fly” or “selectee” lists) are given access to sterile areas within the airport. Often it is incorrectly assumed that passengers in sterile areas do not commit crimes requiring airport law enforcement. Yet, criminal behavior by both passengers and staff in sterile areas is a common place in airports (see Fig. 3).
Fig. 3

Types of crimes committed in sterile areas of airports

Process of Cabin Baggage Screening

Checked baggage screening did not start in the United States until the 1980s, and 100% of check bag screening did not occur until after the passage of the Aviation and Security Act (ATSA 2001). According to Shanks and Bradley (2005), prior to 9/11, less than 5% of checked baggage were screened. Currently the most commonly used technological device for baggage screening is x-ray. Notably, ICAO airports are required to hand search 10–20% (depending on the threat level) of cabin baggage screened by x-ray by hand (International Civil Aviation Organization, 2018).

TSA has incorporated a “screening partnership program” to qualified companies, which operate under federal oversight and comply with both TSA security screening procedures and other perimeter screening regulations. This is due to cost-efficiency, practicality, access to better technologies, or because private companies are more effective than governmental regulated operations (see Grover 2016). Markedly, an investigation carried out by the Government Accountability Office revealed that undercover agents were able to sneak mock explosives/banned weapons through security checkpoints 95% of the time when TSA was responsible for access control (see Grover 2016). As such, security experts have advocated for a more pluralized security approach that incorporates more private security employees working alongside TSA governmental employees.

Hold Baggage Screening

Prior to baggage screening, airlines at baggage check-in ask a series of questions regarding the passenger’s trip and their baggage. Once the baggage is checked in, the baggage goes through primary screening in a secured area of the airport through an explosive detections system (EDS) or an explosive trace detection (ETD). Baggage may also go through alternative screening including manual searches, TSA-certified K-9 bomb detection teams, and positive passenger bag match.

Notably, ICAO airports are required to screen 100% of originating and transferring hold baggage by either hand, conventional x-ray equipment, or explosive detection system (EDS) equipment. If transferred hold baggage has a validation process and continuous implementation of procedures have been established for screening at the point of origin in secured areas, then an exception can be made. If threat levels are elevated, hand searching or advanced x-ray technology must be used 10–20% (depending on the threat level) of hold baggage after initial screening (International Civil Aviation Organization 2018). Currently there is a practical trend for hold baggage to be remotely screened because operators can sit in a control room and the images of bags are allocated and distributed by a computer to different screeners (Wetter 2013). By doing so, this reduces idle times between images and aids screeners in keeping their concentration.

Access Control and Security Within SIDA/AOA Areas

Typically, within SIDA/AOS areas, a working interaction exists between governmental and private-run operations, which incorporate various technological into a layered security module that incorporates access control tactics and strategies. These tactics and strategies in regulating access control involve a working relationship between TSA, law enforcement agencies, and private security agencies often responsible for perimeter security. From a technological standpoint, advanced surveillance incorporates identification readers, closed-circuit television (CCTV), and perimeter intrusion detection systems (PIDS).

Plainclothes Law Enforcement/Undercover Law Enforcement

ICAO calls for the law enforcement patrol of the entire airport and its surroundings and to be available to respond to incidents of unlawful interference with aircraft or airport operations (Price 2018). Often, police personnel are provided by local municipalities (For example, during my police tenure, I was assigned to Hartsfield-Jackson Atlanta International Airport via Atlanta Police. Atlanta is the world’s busiest airport based on passenger traffic (50,251,962 passengers annually) (source: www.atl.com).) or in some cases through an independent airport authority police force. As airport policing requires protecting critical infrastructure, uniformed officers are responsible for responding to security violations at checkpoints, security violations on inbound aircraft, airport employee criminal infractions, vehicular traffic, and irate passengers. As such, airport police must have good customer service skills, good observation skills, community-based tactics, and the ability to distinguish the difference between an upset traveler and a person who is an actual security threat. Besides responding to and investigating crimes in both sterile and non-sterile areas (see Fig. 3), police may conduct plainclothes/undercover proactive investigations. In larger American airports, plainclothes/undercover police often aid in larger-scale investigations involving passengers/baggage alongside federal agencies (e.g., Federal Bureau of Investigations Drug Enforcement Agency; National Security Agency; United States Customs and Boarder Protection; United States Immigration and Customs Enforcement; United States Secret Service; Bureau of Alcohol, Tobacco, Firearms and Explosives; United States Marshals Service; etc.).

Close-Circuit Television (CCTV)

Arguably, there are more CCTVs per square foot in commercial airports than other public areas. Most of these cameras are aimed at security gates, security doors, transition zones between non-sterile and sterile areas, passenger gates, baggage claims, and other publically accessible spaces. Often CCTV footage is monitored alongside security/police responses when a suspicious or heightened alert occurs, assessing unattended baggage from a safe distance, surveillance for theft/human trafficking, documentation for criminal investigations, monitoring of employee controlled access gates, etc.

Airport Perimeter Security

Airside and landside security requirements require effective security that integrates physical barriers, identification and access control systems, surveillance or detection equipment, implementation of security procedures, and effective use of resources (TSA 2006). Notably, since landside facilities are not typically affected by the operation of aircraft, it typically has less stringent security requirements than airside areas. Yet, airside breaches onto airfields through perimeter security are common (see Olivier 2014). Often these breaches are accidental, yet intentional breaches often occur for the following reasons: an attempt to chase down a departing aircraft because an individual has missed their flight, to take a shortcut from one area to another without driving around the airport perimeter, or in rare cases police chases or drunk drivers driving through perimeter gates (Price 2018). In such incidents, the airfield is essentially shut down until the hazard is no longer considered a threat to aircraft on airfields.

Notably, when it comes to airport perimeter security, the FAA, TSA, and the International Civil Aviation Organization (ICAO) all have regulations and suggested practice (see: Olivier 2014). Unlike passenger screening, private security companies often regulate perimeter security. Unarmed security officers often are responsible for perimeter security. As such, their presence, while not law enforcement in nature, is to deter criminal behavior, report suspicious behavior, report violations of airport security, and report any signs of a threat to the airport (Price 2018).

In respect to boundary barriers located in landslide areas, appropriate security boundaries serve to minimize access points. Fencing around security area boundaries often incorporate motion, tension, or other electronic sensing that are monitored by private security sectors. TSA mandates that signage must be visible to identify boundaries between secured areas (1542.201) and AOA areas (1543.203). Based on topography, often chain link fences with barbed wires are established around said perimeters. As such, fences and their monitoring by private security sectors serve as a basic link of deterrence and defense against perimeter breaches (TSA 2006). In regard to technologies, perimeter intrusion detection systems include virtual fences, fence sensor systems, infrared video surveillance systems, visual spectrum video surveillance systems, mobile detection systems, fingerprint readers, and in rare cases unmanned ground and aerial drones (Price 2018). The private security sector, often represented by the American Society of Industrial Security (ASIS), continues to develop perimeter defense technologies along with training and certification for employees who implement said security measures (Price 2018).


The private sector plays an import role alongside governmental agencies that are responsible for security within both sterile and non-sterile areas of airports. Private agencies provide frontline screening and security functions that are supported with the integration of governmental employed police when armed intervention is required (Price 2018). From passenger screening, baggage screening, SIDA/AOA badge credentialing, undercover major investigations to perimeter security, both private and governmental agencies work intersectionally with the overall goal to safeguard civil aviation against unlawful interference.



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Further Reading

  1. Benny, D. (2013). General aviation security aircraft, hangars, fixed-base operations, flight schools, and airports. Boca Raton: CRC Press.Google Scholar
  2. Price, J., & Forrest, J. (2016). Practical aviation security: Predicting and preventing future threats. Oxford: Butterworth-Heinemann.Google Scholar
  3. Rabkin, N. J., Berrick, C. A., & Keisling, C. (2004). Aviation security: Further steps needed to strengthen the security of commercial airport perimeters and access control. Report to congressional requesters. GAO-04-728. Washington, DC: United States General Accounting Office. Available at http://www.gao.gov/new.items/d04728.pdf. Last accessed September 2018.
  4. Szyliowicz, J., & Zamparini, L. (2018). Air transport security: Issues, challenges and national policies. Cheltenham: Edward Elgar.CrossRefGoogle Scholar
  5. United States, Government Accountability Office. (2004). Aviation security: Preliminary observations on TSA’s progress to allow airports to use private passenger and baggage screening services: Report to the Chairman, subcommittee on aviation, committee on transportation and infrastructure, house of representatives. U.S. Government Accountability Office.Google Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Centre for Advanced Policing StudiesLiverpool John Moores UniversityLiverpoolUK