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Right Now

In this issue's Right Now section:
Falling by Wire, Falling by Light - The Cultures of Sweetness and Smoke - "Wonder Cabinets" - Hiking into the Ozone - E-mail and Web Information


Falling by Wire, Falling by Light

Before each takeoff comes a warning, instructing air passengers to turn off computers, radios, headsets, telephones. Tiny amounts of radiation from these electronic devices can leak through cabin windows to antennae on the outside of the airplane, interfering with its operating systems, so Federal Aviation Authority (FAA) regulations proscribe their use. Yet, electronic interference from military equipment outside the plane can be thousands or even millions of times as powerful. Could High Intensity Radiated Fields (HIRFs)--electromagnetic transmissions from radio or radar installations--produced by nearby military ships or planes have caused TWA Flight 800 to crash?

So far, the fruitless inquiry into the disaster, which took 230 lives on July 17, 1996, has considered three possible explanations for the crash: mechanical failure; a bomb inside the plane; and collision with a missile or some other projectile, like a meteorite. This spring, in a 20,000-word article in the New York Review of Books, Elaine Scarry, Cabot professor of aesthetics and the general theory of value, advanced a fourth theory about the crash, involving HIRFs. "Because 10 military planes and ships were in the vicinity of TWA 800 that night," she says, "we need to ask the airmen and sailors on the planes and ships to describe with precision the pieces of equipment that were in use."

Scarry believes that electronic interference could be jeopardizing the safety of all aircraft, both civilian and military. Her research began when she happened on an article referring to a (still classified) 1989 U.S. Air Force study indicating that HIRFs from military planes had occasionally brought down other military aircraft. She wondered whether a commercial carrier like TWA 800's Boeing 747, which includes 150 miles of wiring, might be similarly vulnerable.

Scarry combed through mountains of documents and articles in publications such as Aviation Week and Space Technology, Armada International, and Photonics Spectra. She found items like a 1994 NASA study asserting that HIRFs can affect civilian planes, and a 1997 FAA flight standards bulletin whose title linked HIRFs with lightning as flying hazards that warrant protective measures. Military planes incorporate extensive shielding against HIRFs: one type of U.S. Navy plane, for example, can withstand an electric field of 2,000 volts per meter. Extra shielding costing $175 million now covers the flight computers on the nation's fleet of Black Hawk helicopters, unshielded versions of which crashed at least five times due to electromagnetic interference betweeen 1982 and 1988, causing 22 deaths. "Often when a military plane goes down, it's a blip on the radio news and then it's forgotten," Scarry says.

The effort to avoid unwanted signals also motivates in part the general shift from "fly-by-wire" to "fly-by-light" systems in aircraft. The former uses electric wiring, the latter fiber-optic cable, which is immune to electromagnetic interference. "It is hard to comprehend why High Intensity Radiated Fields should be of sustained concern to the military and yet not even be a subject of discussion when a civilian plane goes down," Scarry asserts. "A great deal of money goes into protecting military aircraft, but there has to be some consideration given to protecting civilian craft as well--or, if it's not necessary, we need to know why not."

In the case of TWA 800, there were at least 10 military craft in the air or at sea at distances possibly within HIRF range of the jetliner at the time of its crash. When the doomed plane reached an altitude of 13,700 feet and began its fall, "directly overhead was a Navy P3 Orion [high-technology electronic reconnaissance plane]...; it was 6,300 feet above the passenger plane and had intersected its longitude and latitude within seconds of the moment the catastrophe began," Scarry wrote. "In the airspace beneath TWA 800, a Black Hawk helicopter and an HC-130 plane were flying at an altitude of 3,000 feet; they were five miles north of the commercial jetliner."

Scarry proposes three hypothetical scenarios that link HIRF interference with the explosion of the 747's central fuel tank, an occurrence deemed nearly as certain as the crash itself. (About 40 seconds after reaching 13,700 feet, the 747 exploded into a giant fireball.) A pulse of energy from outside the plane could have prompted a spike in its high-voltage electric lines, causing current to jump to the low-voltage lines leading to the fuel gauges in the central fuel tank, at one of the places where the two lines are bundled together. This stray electrical charge might have ignited the central fuel tank. At a higher level of field intensity, waves could have ignited vapors from a vent outlet of the fuel tank--as lightning bolts can do: a 1985 FAA document notes that a spark with only a small fraction of lightning's power can ignite a fuel tank. Or, a sudden pulse of energy from a military jammer or countermeasures system could have knocked the plane out of control. "Once a plane begins to fall," Scarry explains, "tearing metal anywhere on the body of the plane can generate sparks, and those sparks might have ignited an explosion in the central fuel tank."

Any or none of these scenarios may have occurred. We do not know and may never know the truth. But Scarry regards the inquiry as incomplete. "If you've got a billion dollars' worth of sensory equipment--radar and sonar--but you're not permitting the men and women who were there to speak, then you've not only lost your most acute sensory apparatus, but your only sensory apparatus that is ethically grounded," she declares. For the safety of both civilians and military personnel, Scarry believes that a sharing of information on HIRFs between military and civilian authorities--and the public--is mandatory. "We are responsible, whether we like it or not, for making sure that the military is held within a civilian frame of reference. This is a very important point in the Constitution," Scarry says. "Today, the military is really off on its own."

~ Craig Lambert

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