Electromagnetic pulse weapons capable of frying the electronics in civil airliners can be built using information and components available on the net (Image: Photolibrary / Getty)
ELECTROMAGNETIC pulse weapons capable of frying the electronics in civil airliners can be built using information and components available on the net, warn counterterrorism analysts.
All it would take to bring a plane down would be a single but highly energetic microwave radio pulse blasted from a device inside a plane, or on the ground and trained at an aircraft coming in to land.
Yael Shahar, director of the International Institute for Counter-Terrorism in Herzliya, Israel, and her colleagues have analysed electromagnetic weapons in development or used by military forces worldwide, and have discovered that there is low-cost equipment available online that can act in similar ways. "These will become more of a threat as the electromagnetic weapons technology matures," she says.
For instance, the US and Russian military have developed electromagnetic pulse (EMP) warheads that create a radio-frequency shockwave. The radio pulse creates an electric field of many hundreds of thousands of volts per metre, which induces currents that burn out nearby electrical systems, such as microchips and car electronics.
Speculation persists that such "e-bombs" have been used in the Persian Gulf, and in Kosovo and Afghanistan - but this remains unconfirmed. But much of what the military is doing can be duplicated by others, Shahar says. "Once it is known that aircraft are vulnerable to particular types of disruption, it isn't too much of a leap to build a device that can produce that sort of disruption. And much of this could be built from off-the-shelf components or dual-use technologies."
It isn't much of a leap to build a device that can produce that sort of disruption in aircraft
For example, government labs use high-energy EMP devices to test what would happen to critical electronic systems if a nuclear weapon detonated, generating a vast electromagnetic pulse, says Robert Iannini, founder of Information Unlimited in Amherst, New Hampshire, which sells EMP test systems.
EMPs can be created in a number of ways. A machine called a Marx generator can quickly dump an extremely high charge stored in a bank of capacitors into an antenna, which then releases a highly energetic radio pulse. Devices like this are often used to test power lines for their resistance to lightning strikes. An alternative, known as a flux compression device, uses a small explosive to push an armature through a current-carrying coil that is generating a magnetic field. This compresses the magnetic field, again producing a devastating EMP.
Iannini says his company only sells such devices to legitimate buyers. "The only people that buy these things are qualified researchers at labs like Sandia. They never find their way into the labs of pseudo or amateur scientists," he says. "If we get any unknown overseas purchaser we immediately alert the office of export enforcement at the US Department of Commerce."
But Shahar told delegates at the annual Directed Energy Weapons conference in London last month that security at some labs can be lax, while basic EMP generators can be built from descriptions available online, using components found in devices such as digital cameras. "These are technologically unchallenging to build and most of the information necessary is available," she says.
The increasing use of carbon-fibre reinforced composite in aircraft fuselages is also making them more vulnerable, she says, because composites provide poor shielding against electromagnetic radiation compared with metal. "What is needed is extensive shielding of electronic components and the vast amount of cables running down the length of the aircraft," she says.
Jerome Bruel, an electrical systems expert at the European Aviation Safety Agency in Cologne, Germany, agrees that newer all-composite planes like the Airbus A350 will probably need some means of protecting their cabling from all radio energy sources, including TV transmitters. "They may need a metal mesh surrounding them to absorb interference," he says.
Douglas Beason, a director at the Los Alamos National Laboratory in New Mexico, says it may be straightforward to build a do-it-yourself EMP weapon, but more difficult to make one that can be stowed in an aircraft. "A lot of work would need to go into dramatically decreasing the weight, shrinking the power supply and antenna," he says.
Nevertheless, governments are taking the threat seriously. A spokesperson at the UK Department of Transport said the government is well aware of this security issue and has close links with agencies "able to provide a balanced picture in regards to EMP weapons, and their potential to compromise civilian aircraft".