Firearms aren’t the only means to foil a hijacking. A variety of non-lethal devices are being hurriedly reviewed. One that is making its way before the FAA, congressional committees, airlines, and unions is the Laser Dazzler, manufactured by LE Systems. It looks like a large flashlight and emits an intense beam of green, pulsating light. The laser is harmless even at close range, but the bursts of light leave those who see them disoriented. The device could also be mounted on an aircraft bulkhead and, should there be a threat in the cabin, activated by a remote switch.
Another defensive weapon can be the aircraft itself. In a normal flight, says Captain John Cox, ALPA executive air safety chairman, “the idea is don’t spill the coffee. But with a hijacker on board, a 2-G maneuver would double his weight, and that could help disable him.” There are risks, though, in attempting aerobatics with an airliner. Cox issued a bulletin to ALPA members warning, for example, that loose objects can be turned into projectiles and that “aggressive, sustained control inputs, especially at high altitudes, may cause an aircraft upset that could lead to loss of control.” The DOT’s rapid response team recommended that such maneuvers, including dives and intentional depressurization, be used only as a last resort.
The September 11 hijackers succeeded not only in diverting four aircraft but also in keeping ground authorities largely in the dark while they did so. Many technological fixes are being proposed to prevent that from happening again. These include a transponder that continues to transmit aircraft identification, altitude, and hijack signal, even if switched off from the flight deck. Honeywell is considering some form of “panic button” that would immediately downlink the data that is routinely stored in the cockpit voice recorder and digital flight data recorder.
Remember HAL, the computer with a mind of its own in the movie 2001: A Space Odyssey? Picture hijackers aiming 767s at the World Trade Center and the aircraft, like HAL, refusing to do as commanded. Such a safeguard appears feasible. Even before September 11, NASA was exploring a number of “refuse to crash” technologies that would keep pilot mistakes from leading to accidents. Enhanced ground proximity warning systems (EGPWS) are already in use. Coupled to the radar altimeter, plain-vanilla EGPWS warns the pilot when the airplane is too close to the ground. The enhanced version consults a terrain database to warn that there’s a likely collision ahead. To turn this system into a hijacking countermeasure, those advisories would have to be converted into orders.
The next step could be to wrest control from the pilot altogether. Once a hijack attempt becomes evident, someone on the ground takes over and flies the airplane. James Coyne, president of the National Air Transportation Association (NATA), says that most of the ingredients for this scenario are already in use, such as flight management systems, fly-by-wire control, and auto-land capability. What’s still missing, he says, is a long-awaited broadband data link, which would replace much of the routine voice communication between air and ground. ALPA representatives, among others, are more skeptical. They point to the risk of accidental or even intentional misdirection from remote aircraft operators, and FAA spokesman Les Dorr classifies such technologies as long-term, since even the military has perfected remote control only with relatively simple, single-engine aircraft.
Of course it’s a lot safer to prevent a hijacking than to foil one in progress. That entails keeping terrorists, weapons, and bombs off aircraft in the first place. ALPA’s testimony to the U.S. Senate recommended 30 near- and long-term actions to improve airline safety. For example, the union suggested that the Immigration and Naturalization Service not be allowed to use scheduled airline flights to deport illegal aliens without the escort of armed INS agents. Currently, the INS allows up to 10 deportees to travel unescorted on a flight with paying passengers.
In the aftermath of September 11, private security companies and the airlines that hire them have come under fire. Poorly trained, underpaid screeners often miss the test weapons used to gauge their performance. Suddenly there has been agreement on the need to federalize or otherwise upgrade the screener workforce. (As this issue went to press, the U.S. Congress had not reached agreement on an aviation security bill dealing with, among other items, airport security personnel.) But new regulations and technology can also enable existing screeners to do a better job. Reducing the number of carry-on bags allowed per passenger will enable each bag to receive closer scrutiny by screeners.
Twenty years ago, the FAA was supporting research into the use of gerbils as sniffers to detect explosives. Bag-screening technology has come a long way since then. Computed tomography—CT scanning— takes multiple X-rays of a bag to produce a three-dimensional image of its contents. Quantum Magnetics has produced a scanner that uses magnetic resonance imaging to search for hard-to-find explosives, such as plastic explosive rolled into a sheet and sewn into the side of a briefcase. The problem with these machines is their cost. The biggest scanner by InVision Technologies can handle up to 800 bags per hour, but each unit costs $1.5 million. According to Charles Barclay, president of the American Association of Airport Executives, the latest explosive detection systems are in service at only 46 airports across the country.
Perhaps the most problematic of security challenges is the screening of passengers. The FAA and Northwest Airlines developed the Computer-Assisted Passenger Pre-Screening System, which profiles passengers based on information in an airline’s reservation system, such as if the ticket was puchased with cash or if the ticket is one-way. So far, though, CAPPS has been applied only to passengers who stop at an airline ticket counter, usually to check baggage, before proceeding through security.
There is also a need to ensure that the people who board airplanes are the same ones who bought the tickets and went through airport security checkpoints. One proposed security system would photograph all passengers with their checked luggage. Each photograph would be encrypted on the passenger’s ticket in the form of a bar code. When the ticket is scanned by an airline agent at the boarding gate, the agent’s computer monitor would display the photograph of the ticket-holder. If the two faces don’t match, the traveler would be denied boarding. The same technology could also be used to match passengers with their bags, so that any unmatched bags could be removed from an aircraft prior to takeoff. The technology exists, but implementation will depend on approval by the FAA.