Devices to Increase Airport Security
Sept. 14, 2001 -- Investigators are still trying to piece together how terrorists managed to smuggle knives onto the four airplanes used in Tuesday's attacks. But security experts predict that detecting weapons and preventing future hijackings will require many changes — and new technologies.
Leo Boivin, a former manager with the Federal Aviation Administration, says the metal detectors and X-ray scanners in most airports are quite sophisticated.
"In the last few years, most carriers have upgraded to good machines," says Boivin, who used to conduct tests on airline security personnel at overseas airports for the FAA.
Still, "Trying to find knives at airport checkpoints is tough," he says. "The average carry-on [bag] has more stuff in it than ever before and it makes it harder to find."
And, he notes, several sportsmen's catalogs sell knives made of non-metallic material, making them impervious to metal detectors. "Even if you put it in your front pocket," says Boivin, "It wouldn't ring the detector."
New Detection Methods
That may all change as more companies begin to rapidly develop and introduce advanced detection systems.
One new X-ray machine developed by Rapiscan Security Products, for example, is designed for use on passengers rather than on carry-on baggage. The Hawthorne, Calif., company's Secure 1000 looks like a large gray wardrobe closet and uses a narrow beam of low-powered X-rays to scan a passenger. The X-rays penetrate a few millimeters into the body and reflected back to sensitive detectors.
Soft objects such as flesh and clothing reflect weak signals while harder objects — guns, knives, coins, or even plastic explosives — will return stronger signals. Advanced software and computers can process these signals and convert them to images in which the hard objects are clearly outlined.
The company claims that the three-second exposure to the machine's X-rays aren't any more harmful than the natural exposure to radiation that most travelers experience in 20 seconds of flight on a conventional airplane.
No Harm Here
Other companies are working on similar imaging technologies that don't use harmful X-rays.
Trex Enterprises, a company in San Diego, is testing a so-called passive millimeter wave camera with the National Institute of Justice, the research arm of the Justice Department. Much like an infrared camera, the Trex device can detect hidden objects by measuring differences in invisible heat energy emitted by a person's body and the concealed object.
The device is similar to other radar-like hidden weapon detectors being tested at NIJ. But Stuart Clark, the program manager for concealed weapons detection at Trex, says that their system is totally safe in that it emits no radio or other harmful waves. Such a passive system may be more agreeable to passengers than systems that actively scan bodies with X-rays.
Still, such advanced detection systems as Rapiscan's unit may cost as much as hundreds of thousands of dollars per unit. Most walk-through metal detectors, on the other hand, cost only tens of thousands of dollars.
And other such systems are still just laboratory prototypes — years away from deployment at airports. What's more, some advanced detectors such as Trex's archetype may bring up privacy and Fourth Amendment concerns — concerns that, balanced against security, have been cast in a new light.