The FBI and Department of Homeland Security are warning law-enforcement agencies to look out for laser-wielding terrorists. Lasers, a recent memo states, could be used to blind commercial airline pilots just prior to landing. Anyone who's ever used a laser pointer might be a bit skeptical of the alert, however, given how difficult it is to fix the beam on a stationary spot a few dozen meters away—to say nothing of a passenger jet zooming toward an airport runway. How feasible is this laser attack, really?
Quite feasible, assuming the terrorists can get their hands on some military-grade hardware designed for exactly this purpose. The Chinese-made ZM-87 is perhaps the best known of these blinding weapons, also known as laser dazzlers. It was designed to foil night-vision equipment and burn the retinas of enemy troops and has an effective range of up to 10 kilometers. The device is usually mounted on tanks, though there are reports that it's been added to the decks of naval vessels, too. China North Industries Corporation, better known as Norinco, has been manufacturing and selling the ZM-87 since roughly 1995.
The Chinese are not the only military power curious about the offensive capabilities of lasers. The Russians are reputed to have developed a similar dazzler, which may have been involved in a 1997 incident in which a U.S. Naval intelligence officer claims his eyesight was permanently damaged during a helicopter mission in the Straits of Juan de Fuca. (Click here for the latest on that controversial saga, which has become a minor cause célèbre.) The United States has also tinkered with dazzlers of its own, though its focus is apparently more on short-range disruptors that can be attached to rifles.
None of this hardware is easily obtainable, so a terrorist might be more likely to invest in a consumer-grade laser system, of the sort used in outdoor light shows. Such systems can be had for as little as a few thousand dollars and pack enough eye-burning wallops to get the job done. In fact, pilots have often complained about the inadvertent threat of errant laser-show lasers; in 1995, for example, laser shows on the Las Vegas Strip were temporarily suspended, due to the safety objections of airlines that use the city's nearby airports. It took over four years for the outdoor shows to return, after the operators drew up usage guidelines guaranteeing that no errant beams would hit passing cockpits.
It's also possible, albeit unlikely, that a high-powered laser pointer could wreak havoc on a pilot's sight. There are some imported pointers that are unusually intense, and the FBI has warned that criminals may be bundling these devices together to create homemade dazzlers capable of reaching 1,500 feet into the air.
The trick, of course, is being able to hit the pilot square in the eyes through the cockpit glass—a feat that would require an extraordinary amount of luck. But it's not impossible, as evidenced by a September incident near Salt Lake City International Airport in which a Delta Air Lines pilot suffered a burned retina due to a laser beam. The source of that laser is still unknown.
An effective dazzler attack on a commercial plane may be highly unlikely. A bigger concern is the use of lasers during aerial combat; temporary disorientation during a dogfight, for example, could be disastrous. The Navy has developed a device called the Laser Event Recorder, which warns pilots when lasers are bombarding their cockpit. The Army Research Office is also funding a project at the University of Central Florida that's looking into visors that darken automatically when bombarded with lasers.