> home
> About
> Contact Us
> Editorial Info
> IEEE-USA

08.11

How Safe Are We in Air Travel?

Two recent hearings by the House Oversight and Government Reform Subcommittee on National Security, Homeland Defense and Foreign Operations explored the current state of air travel safety. The first hearing, held on 16 March, entitled, "TSA Oversight Part 1: Whole Body Imaging" examined issues associated with the use of imaging technology, including effectiveness, privacy concerns, and health risks. The second hearing, “Airport Perimeter Security,” on 13 July, investigated the security of U.S. airports’ physical boundaries.

There are 457 airports in the United States with commercial flights. A program called Joint Vulnerability Assessment (JVA), conducted by the Federal Bureau of Investigation and the Transportation Security Administration, reviewed 13 percent of these airports between 2004 and 2008 ( that figure is closer to 17 percent today). The crucial element limiting a broader review is FBI availability. John Sammon of TSA says that TSA does its own risk assessment of each airport annually.

The routine for passenger screening has been called “security theater” — giving passengers a sense of security that may not be grounded in the actual measures taken. It is based on past threats. For months following the 9/11 attack on the Pentagon, flights to and from Reagan National Airport required that passengers remain in their seats for the 45 minutes closest to the airport. The requirement was removed when all the cockpit doors had been reinforced with locks installed. Air marshals fly on selected flights. When the shoe bomber attempted to take down a plane in 2001, the ground passenger screening was expanded to require removal of shoes in the U.S. and some other countries.

Removal of jackets and other outer clothing came next. When intelligence tips thwarted a 2006 plot in England to carry onto aircraft liquids which could be combined into explosives, liquids were limited in volume and had to be placed in clear plastic bags for inspection. 

Explosives Trace Detection (ETD) was used at random (typically once per hundred passengers) to analyze material swabbed from openings in carry-on bags or from hands to detect explosives.  Metal detectors (magnetometers) had been in use since the 1970s for passenger screening to detect weapons that could be used in hijackings. Since the early threat was diversion of aircraft to Cuba to release dissidents, crews were instructed not to take action against them. All aircraft that could be diverted carried charts for Cuba. (Any attempt at hijacking today would likely be met by passengers rising up to quell the attempt.)

The puffer debacle

Starting in 2004, a technology was deployed for airport passenger screening after going through metal detectors that used puffs of air retrieved after passenger contact, for analysis to detect residue from explosives and illegal drugs in less than 20 seconds. The machines (“puffers”), costing about $160,000 each, were found to be unreliable in airport environments and were withdrawn after $30 million had been spent on them. At their peak, 94 puffer machines were installed at 34 airports. TSA planned to install 434 machines before the program was aborted with 207 machines already built. TSA spent $6.2 million on maintenance. Nearly $1 million was spent removing the machines. 

Need for better non-metallic object detection

The need for detection of non-metallic objects was reinforced by the “underwear bomber” wearing plastic explosive sewn into his underwear. He ignited his clothing and a wall panel in the aircraft but was unsuccessful in detonating the explosive at the end of a flight from Amsterdam to Detroit in December 2009. His father had called authorities to warn of his son’s activities after receiving a disturbing phone call from the son.

The successor is Advanced Imaging Technology (AIT) deployed in full-body imaging machines.  About 488 of these machines are now installed at 78 airports. The public was not well-prepared to cope with these machines, which yield an image equivalent to an unclothed body. Where the machines were installed, the flying public was given the choice of a pat-down by a TSA agent of the same sex as the flyer rather than the body scan, in a private (screened) area if desired. Further reactions to adverse criticism was to make it known that body images would not be stored by the machine, and that the image display would not be shown in a public area. That increased the manpower requirement — one agent to detain the flyer for whichever screening was preferred, one to review the full body scans, and one to operate the radio link between the back room with the display and the line of passengers being processed. The average cost of a TSA agent is $75,000 per year. A body scan machine costs about $175,000. There are two alternative technologies used. One is millimeter wave while the other is x-ray backscatter. The millimeter wave does not produce a cancer risk, while the low-dosage x-ray backscatter technology has a cancer risk of one in 10 million, according to Dr. David Brenner, of the Center for Radiological Research at Columbia University. The number of people screened per year now is 700 million, with more expected in the future. With one billion scans annually there could be 100 cancers caused per year with the backscatter dosage. TSA maintains that both technologies are needed to maintain competition in the procurement process, and that the risk from the x-ray backscatter technology is negligible.

TSA recently began installing new software on its millimeter wave imaging technology machines — upgrades designed to enhance privacy by eliminating passenger-specific images and instead auto-detecting potential threats and indicating their location on a generic outline of a person.

These machines have limited utility in detecting substances implanted under the skin or in body cavities. Surface bumps from an implantation can be detected.

Profiling and privacy

TSA is sensitive to charges of profiling if people are treated differently in screening. This has resulted in very young children and wheelchair-bound grandmothers being subjected to the same screening as able-bodied males. A different risk-based approach is used at the Ben Gurion Airport in Tel-Aviv, where passengers are questioned and watched for their reactions.

A screening program for passengers, called SPOT (Screening of Passengers by Observation Techniques), aims at detecting behavioral anomalies by passengers approaching checkpoints. A budget request of $250 million follows on $750 million already spent on the program.  SPOT is deployed at 161 airports, but the underlying science is still being validated. The GAO has reported on SPOT and other efforts to improve security.

Privacy rights have been voiced by some with respect to full body scanners and pat-downs. Public input to TSA was sought on body imaging scanners after a U.S. appeals court recently found them constitutional. The Electronic Privacy Information Center had sued the TSA last year, calling the full-body scans  “the most sweeping, most invasive and the most unaccountable suspicionless search of American travelers in history.”

Chief Judge Douglas Ginsburg said, “Despite the precautions taken by the TSA, it is clear that producing an image of the unclothed passenger … intrudes on his or her personal privacy in a way that a magnetometer does not.” But this technology can detect non-metallic explosives to prevent their being carried aboard an airplane, so its use is justified.

Upgraded software for airport body scanners will do away with naked images, showing instead a generic body outline highlighting any anomalies detected.  The 241 millimeter-wave machines deployed at 40 airports will get the upgrade in the next several months. Backscatter scanners will be tested later this year. In 38 airports, 247 of these machines are deployed.

A pilot program to speed up the processing of frequent fliers will be rolled out at four airport hubs — Atlanta, Dallas-Ft. Worth, Detroit, and Miami. This identity-based program, called Trusted Traveler, implies a risk assessment rather than the same security model for all passengers. Expedited screening could permit a traveler to keep his or her shoes on and also not be required to take a laptop out of the bag for X-ray. It is estimated that 5,000 to 8,000 U.S. citizen travelers could benefit from the program, out of the 1.8 million who go through security checkpoints daily.

Another program, called CLEAR, uses biometric and fingerprint identification and is available at the Denver and Orlando airports. For registered participants (who pay $179 per year, plus $50 for an additional family member) there is a fast lane to the head of the line for security screening.

Passenger screening not the only answer

There have been 25,000 known security breaches at our 457 airports in the past ten years. There are over 900,000 security badges to keep track of, and perimeters to monitor and safeguard. A quarter-mile of perimeter fencing is missing around the JFK airport. Corrective efforts are four years behind schedule. LAX has 8 miles of fence installed over time, with no consistent standard.

A Joint Vulnerability Assessment, to be conducted by the TSA with FBI every three years for airports considered to be at high risk, has not been accomplished for 83 percent of airports.

An example of a security breach past the passenger screening line occurred at Orlando in 2007. Two baggage handlers carried a bag containing guns and drugs on a commercial flight from Florida to San Juan, Puerto Rico. The baggage handlers used their employee uniforms and airport identification cards to enter restricted areas, bypass screeners with the bag and board a commercial Delta flight. They were apprehended after a tip to police. Several trips had been made running guns and drugs. 

In another case, in 2010 a teenager sneaked into the Charlotte airport and stowed away in a wheel well of an aircraft bound for Boston. He fell out near Logan Airport when the wheels were lowered for landing. Death may have occurred by crushing when the wheels were retracted, from loss of oxygen at altitude or by freezing in the -30 degree temperature at 35,000 feet.

In the subcommittee hearing on airport perimeter security Rep. John Mica (R-Fla.) lamented the TSA’s “unthinking non-risk-based bureaucracy.” Mica is chair of the full House Transportation and Infrastructure Committee.

Baggage scanning

The first requirements for scanning of checked baggage were issues in 1998. These were later tightened in 2005 and further in 2010. The Electronic Baggage Scanning Program detection capability now in place meets the requirements for 1998 or 2005, not for 2010.

 Passengers concerned about theft from their checked bags can use TSA-approved locks that can be opened by agents then re-closed after inspection.

Are dogs coming to an airport near you?

Amtrak has a K-9 unit used to screen passengers unobtrusively. After two years of training, dogs can function for 6 to 8 years detecting threats including explosives and drugs. Amtrak uses dogs for morning sweeps of passenger loading areas and to monitor boarding gates. “Vapor wake” is one application for dogs. Up to 15 minutes after a threat has passed, dogs can detect the threat.

At a recent congressional hearing, Inspector William Parker of Amtrak Police demonstrated the ability of dogs to detect drugs and explosives. One dog was able to pick out of a line of people walking by the one who had 5 pounds of smokeless power in ankle weights. The dog pulled his handler to follow the suspect. In a second demonstration after subjects had been seated, a dog was bought in and found the woman who had traces of explosive on her garments. Dogs can function for 2 to 3 hours at a time. Parker pointed out that machines depreciate but dogs don’t. TSA has begun using dogs on a limited basis.

On July 9, a dog working with Customs at the Orlando airport sniffed out cocaine pellets in the stomach of a Nigerian man bound for London. He had swallowed 54 pellets in Houston, totaling 933.2 grams, to smuggle out of the country.

After a drug dog pointed to him, an X-ray showed foreign bodies in his digestive tract. Some were passed naturally, with the remainder removed surgically before the man was moved from a hospital to jail.

The Department of Defense has spent $19 billion to train dogs to detect Improvised Explosive Devices in Iraq and Afghanistan through the Joint Improvised Explosive Device Defeat Organization (JIEDDO). 

Trusted Travelers

Individuals who have been vetted and need only identity verification to enjoy a less rigorous search procedure represent a way to shorten the TSA security lines. Hand-held facial recognition devices are planned for introduction by dozens of law enforcement agencies from Massachusetts to Arizona, as soon as September. The device, attached to an iPhone, can snap a picture of a face from 5 feet away, or scan irises from 6 inches away. An immediate database search can be done to find any criminal record. Fingerprints can also be collected. The database is not yet complete, but this portable technology has been in use in Iraq and Afghanistan to identify possible insurgents.

http://blogs.wsj.com/digits/2011/07/13/how-a-new-police-tool-for-face-recognition-works/

Some privacy issues are raised, such as whether its use in certain ways could constitute a search that requires a warrant. But if the devices are widely adopted cost will be low and some travelers would gladly waive search charges in exchange for faster airport processing.

Some airports now have multiple security screening lines, such as ones for families, ones for other infrequent travelers, and ones for expert travelers who know the drill. A few have separate lines for elite travelers who are frequent fliers. These improvements may shorten the wait to be screened, but the screening itself is not affected.

One airport visited recently had TSA signs that laptops could stay in their bags for screening, but a TSA official said this is not yet the policy.

George F. McClure is Technology Policy editor for IEEE-USA Today’s Engineer and the IEEE Vehicular Technology Society's representative to IEEE-USA's Committee on Transportation and Aerospace policy.

Comments may be submitted to todaysengineer@ieee.org.