Large numbers of people pass through airports. Such gatherings present a target for terrorism and other forms of crime due to the number of people located in a small area. Similarly, the high concentration of people on large airliners, the potential high lethality rate of attacks on aircraft, and the ability to use a hijacked airplane as a lethal weapon provide an alluring target for terrorism.
Airport security provides a first line of defense by attempting to stop would-be attackers from bringing weapons or bombs into the airport. If they can succeed in this, then the chances of these devices getting on to aircraft are greatly reduced. As such, airport security serves two purposes: To protect the airport from attacks and crime and to protect the aircraft from attack.
Monte R. Belger of the U.S. Federal Aviation Administration notes "The goal of aviation security is to prevent harm to aircraft, passengers, and crew, as well as support national security and counter-terrorism policy.
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Some tragedies have been the result of travellers being permitted to carry either weapons or items that could be used as weapons on board aircraft so that they could hijack the plane. Travellers are quickly screened by a metal detector. More advanced explosive detection machines are being used in screening such as X-ray machines. Explosive detection machines can also be used for both carry on and checked baggage. These detect volatile compounds given off from explosives using gas chromatography . A recent development is the use of backscatter X-ray scanners to detect hidden weapons and explosives on passengers. These devices, which use Compton scattering, require that the passenger stand close to a flat panel and produce a high resolution image .
Generally people are screened through airport security into the concourses, where the exit gates to the aircraft are located. This area is often called a secure or sterile area, and is referred to as airside. Passengers are discharged from airliners into the sterile area so that they usually will not have to be re-screened if disembarking from a domestic flight; however they are still subject to search at any time. Eating establishments have started using plastic glasses and utensils as opposed to glasses made out of glass and utensils made out of metal to reduce the usefulness of such items as weapons.
Non-passengers were once allowed on the concourses to meet arriving friends or relatives at their gates, but this is greatly restricted now in the United States. Non-passengers must obtain a gate pass to enter the secure area of the airport. The most common reasons that a non-passenger may obtain a gate pass is to assist children and the elderly as well as for attending business meetings that take place in the secure area of the airport. In the United States, at least 24 hours notice is generally required for those planning to attend a business meeting inside the secure area of the airport.
In some countries, specially trained individuals may engage passengers in a conversation to detect threats rather than solely relying on equipment to find threats. In the United States the TSA has run several dummy tests in several major airports to measure the success of catching people with bombs. In 2002, the TSA reported that roughly 60% of fake bombs or component parts to bombs were missed by covert screeners. In 2007, that percentage rose to 75%, although this statistic alone is misleading. The tests are done by using undercover agents to carry fake bombs/parts in their carry on luggage and counting how many are successful with getting through security checkpoints. The TSA runs covert tests every day and when a screener misses an undercover agent carrying dangerous items, they are immediately sent to remedial training. Throughout the world, there have been a few dozen airports that have instituted a version of a "trusted traveller program". Proponents argue that security screening can be made more efficient by detecting the people that are threats, and then searching them. Searching trusted, verified individuals should not take the amount of time it does and biometrics will help to solve this problem.
Another notable failure was the 1994 bombing of Philippine Airlines Flight 434, which turned out to be a test run for a planned terrorist attack called Operation Bojinka. The explosion was small, killing one person, and the plane made an emergency landing. Operation Bojinka was discovered and foiled by Manila police in 1995.
On May 30, 1972 three members of the Japanese Red Army undertook a terrorist attack, popularly called the Lod Airport massacre, at the Lod Airport, now known as the Ben Gurion International Airport, in Tel Aviv. Firing indiscriminately with automatic firearms and throwing grenades, they managed to kill 24 people and injure 78 others before being neutralized (one of them through suicide). One of the three terrorists, Kozo Okamoto, survived the incident.
The Rome and Vienna airport attacks in December 1985 were two more instances of airport security failures. The attacks left 20 people dead when gunmen threw grenades and opened fire on travelers at El Al airline ticket counters.
On August 10, 2006, security at airports in the United Kingdom, Canada, and the United States was raised significantly due to the uncovering by British authorities of a terror plot aimed at detonating liquid explosives on flights originating from these countries. This is also notable as it was the first time the US Terror Alert Level ever reached "red". The incident also led to tighter restrictions on carrying liquids and gels in hand luggage in the EU, Canada, and the United Sates.
CATSA uses x-ray machines to verify the contents of all carry-ons as well as metal detectors, explosive trace detection (EDT) equipment and random physical searches of passengers at the pre-board screening points. X-ray machines, CTX machines, high-resolution x-rays and EDTs are also used to scan checked bags. All checked baggage is always x-rayed at all major commercial airports.
CATSA also completed the first phase of its Restricted Area Identity Credential (RAIC) program in January 2007. This program replaces the old Airport Restricted Area Passes issued to airport employees after security checks by the Canadian Security Intelligence Service, the Royal Canadian Mounted Police and Transport Canada with new cards (issued after the same checks are conducted) that contain biometric information (fingerprints and iris scans) belonging to the person issued the RAIC.
The RAIC has yet to be extended to the security perimeter of Canadian airports for vehicles and persons entering from checkpoints not within airport terminals.
While CATSA is responsible for pre-board passenger and random non-passenger screening, they contract out to third-party "service providers" such as Aeroguard and Garda to train, manage and employ the screening officers. In addition, individual airport authroties which were privatized in the 1990s by the Canadian Government are responsible for general airport security rather than CATSA and normally contract out to private companies and in the case of large airports, pay for a small contingent of local police officers to remain onsite as well.
The Hong Kong International Airport is secured by the Hong Kong Police Force and Aviation Security Company (AVSECO). Within the police force, the Airport District is responsible for the safety and security of the airport island. Airport Security Unit (ASU) members are deployed around the airport and are armed with H&K MP5 A3 Submachine Gun. The security of the restricted area is the responsibility of the police and AVSECO.
While the airport is under the control of the Airport Authority Hong Kong (AAHK), the security power has been delegated to the AVSECO staffs. All persons and baggages carried by them must be X-Rayed and checked at the security screening points of the AVSECO (with a few exceptions at the Tenant Restricted Area).
The Customs and Excise Department will check passengers and crews' luggage to discourage smuggling of drugs and contraband from entering Hong Kong. New regulations have been made similar to Europe as of April 2007, no liquids can be brought onto a plane which exceed 100ml.
Terrorist threats and narcotics are the main threats in Indian airports. Another problem that some airports face is the proliferation of slums around the airport boundaries in places like Mumbai. Before boarding an aeroplane, searching of hand luggage is likely.
Security for the country's two international passenger airports comes under the purview of the Airport Police Division of the Singapore Police Force, although resources are concentrated at Singapore Changi Airport where scheduled passenger traffic dominate. Seletar Airport, which specializes in handling non-scheduled and training flights, is seen as posing less of a security issue. Since the September 11, 2001 attacks, and the naming of Changi Airport as a terrorism target by the Jemaah Islamiyah, the airport's security has been stepped up. Roving patrol teams comprising of two soldiers and a police officer armed with machine guns patrol the terminals at random. Departing passengers are checked at the entrance of the gate rather than after immigration clearance like Hong Kong International Airport. This security measure is easily noticed by the presence of X-Ray machines and metal detectors at every gate which is not normally seen at other airports.
Assisting the state organizations, are the security services provided by the ground handlers, namely that of the Singapore Airport Terminal Services's SATS Security Services, and the Aetos Security Management Private Limited, formed from a merger of the Changi International Airport Services's airport security unit and that of other companies to become a single island-wide auxiliary police company. These officers duties include screening luggage and controlling movement into restricted areas.
Since 2005, an upgrade in screening technology and rising security concerns led to all luggage-screening processes to be conducted behind closed-doors. Plans are also in place to install over 400 cameras to monitor the airport, to discourage bomb attacks similar to the 2005 Songkhla bombings in Southern Thailand where Hat Yai International Airport was targeted. Tenders to incorporate such a system were called in late September 2005 .
From 7 January 2008, travellers are no longer limited to a single piece of carry-on luggage at most of the UK's major airports Currently, hand luggage is limited to bags that are no larger than 56 cm (22.0 in) tall, 45 cm (17.7in) wide, 25 cm (9.8 in) deep. Certain airlines have more stringent rules.
Passengers are not permitted to take any liquids over 100 ml past security, although liquids in larger containers purchased in the secure area are allowed on flights. Any liquids under 100 ml must be placed in "a single, transparent, re-sealable plastic bag (about the size of a small freezer bag), which itself must not exceed 1 litre in capacity (approximately 20cm x 20cm).
All bags are screened via X-ray before being put on the plane. All passengers must walk through metal detectors. Human airport security has also been increased and people are highly likely to be searched. There are also the usual checks of passports and boarding cards. On-line check-in is also now in use.
The UK is considering new methods of screening passengers to further improve airport security, such as advanced X-ray machines that provide a 360-degree view of a person, as well as "see" under clothes, right down to the skin and bones.
Prior to the 1970s American airports had minimal security arrangements to prevent aircraft hijackings. Measures were introduced starting in the late 1960s after several high-profile hijackings.
Sky marshals were introduced in 1970 but there were insufficient numbers to protect every flight and hijackings continued to take place. Consequently in late 1972, the FAA required that all airlines begin screening passengers and their carry-on baggage by January 5, 1973. This screening was generally contracted to private security companies. Private companies would bid on these contracts. The airline that had operational control of the departure concourse controlled by a given checkpoint would hold that contract. Although an airline would control the operation of a checkpoint, oversight authority was held by the FAA. C.F.R. Title 14 restrictions did not permit a relevant airport authority to exercise any oversight over checkpoint operations.
The September 11, 2001 attacks prompted even tougher regulations, such as limiting the number of and types of items passengers could carry on board aircraft and requiring increased screening for passengers who fail to present a government issued photo ID.
The Aviation and Transportation Security Act generally required that by November 19, 2002 all passenger screening must be conducted by Federal employees. As a result, passenger and baggage screening is now provided by the Transportation Security Administration (TSA), part of the Department of Homeland Security. Provisions to improve the technology for detecting explosives were included in the Terrorism Prevention Act of 2004.
Noticing the demand for new technology in airport security, General Electric (GE) started to develop the Secure Registered Traveler System. The new system would use newly developed technology such as automated carry-on scanning, automatic biological pathogen detection, millimeter-wave full body scanning and a quadruple resonance carpet that would detect threats in shoes without having to take them off. The SRT program also works with smartcard technology along with fingerprint technology to help verify passengers. The fingerprint scanner also detects for explosive material traces on the person's fingers. These technologies will provide a more detailed search that is less intrusive to the passengers. Millimeter waves are less harmful than the previous X-rays.
With the increase in security screening, some airports saw long queues for security checks. To alleviate this, airports created Premium lines for passengers traveling in First or Business Class, or those who were elite members of a particular airline's Frequent Flyer program.
The "screening passengers by observation techniques" (SPOT) program is operating at some U.S. airports.
On February 27, 2006, at the Will Rogers World Airport in Oklahoma City, in an airliner cargo area (accessible only to authorized personnel), threatening graffiti was found.
On March 6, 2006 at John F. Kennedy International Airport in New York, an elderly man drove his car onto the runway through two security gates. He made it to an active runway where an Air France aircraft was preparing to land. The man drove around for approximately 23 minutes before being stopped. On the same day a man made it on to the runway by running though a secure gate while it was being opened at Midway International Airport in Chicago. The man made it through one of the three perimeter entrances that did not have a camera, resulting in four different runways being closed down. This incident led to 222 aviation security officers being retrained and a redesign of all perimeter gates.
On March 11, 2006, after four years of continuous security breaches and staffing problems news reports indicated that federal officials removed the head of security at Newark Liberty International Airport.
On March 31, 2006, at Honolulu International Airport two baggage screeners pleaded guilty to stealing thousands of dollars in yen from outbound Japanese tourist luggage. According to prosecutors, the baggage screeners were part of a group of screeners who stole money from outgoing luggage and divided the money amongst the group.