Technology

Poor Man's Air Force: Terrorists and Light Aircraft

By Dave Majumdar, Special to Aviation.com

posted: 04 September 2008 04:18 pm ET

: While unlikely to be able to carry a weapon of mass destruction to a U.S. target, a small fleet of cheap ultralight or light sport aircraft could represent a potent attack threat to U.S. interests, particularly overseas, in the hands of a group of resourceful terrorists. Credit: Paul Burke
: Homeland Security Secretary Michael Chertoff has said he is concerned about the possibility of a terrorist cell converting a high-performance, relatively inexpensive small jet such as the Eclipse Aviation EA-500 to fly by remote control with a weapon of mass destruction to a near-border U.S. target. However, some defense analysts see the threat as unlikely, believing other kinds of attack are much more credible. Credit: David Atkinson
: The Czech-built Zlin Z-143 light general aviation and aerobatics aircraft is in use with some smaller air forces as a primary trainer. It has also been used by anti-government rebels: In Sri Lanka the Tamil Tigers modified some Z-143s to create improvised bombers and used them to bomb Colombo International Airport, the country's major commercial air gateway, on March 26, 2007. Credit: Dr. C.R.R. Char, Varman Aviation Pvt. Ltd.
: Ultralight aircraft and para-gliders can be, and have been, used as terrorist weapons, most notably in a November 1987 on an Israeli border post. While slow and relatively fragile, they are particularly hard for conventional forces to guard against effectively, particularly in border areas. This is because they can take off in short distances from almost any road or flat grassy surface and can fly slowly and very low to avoid detection. Credit: Paul Burke

The scenario that follows isn't real, but Homeland Security Secretary Michael Chertoff is concerned about the possibility that it could happen.

An Eclipse 500 very light jet streaks across the sky towards San Diego from a remote desert airstrip in South Baja, Mexico. Onboard, there is no pilot, and in the passenger cabin there are no passengers.

Instead, a refrigerator-sized metal box rests where normally there would be seats. Further forward, in the cockpit, the flight controls have been extensively modified to allow the plane to be operated remotely without a pilot.

The course of the very light jet (VLJ) has been carefully plotted so it will fly low over the sea between the Mexican mainland and the Baja Peninsula. As it approaches the thin southern US Air Defense Identification Zone, the very light jet dips further towards the Earth, using the mountains to shield its approach from North American Air Defense Command (NORAD) radars.

Traveling at close to 400 knots (460 mph) at low altitude, the VLJ crosses the 100 miles to the U.S. border near San Diego in less than 15 minutes.

By the time NORAD scrambles alert fighters to intercept the wayward plane, it is too late. The Eclipse 500 crosses the airspace over San Diego. An instant later, as a brilliant flash illuminates the night sky, most of San Diego ceases to exist.

It is this kind of nightmare scenario — the specter of a terrorist cell using a private jet to transport a weapon of mass destruction into the United States — that keeps Chertoff up at night, he said during a March 6 briefing.

Means for aerial attack "readily available"

“For over a decade the intelligence community has been warning us about poor states or non-state actors attacking us with cruise missiles or unmanned aerial vehicles (UAVs). The technology is cheap and readily available,” said Loren Thompson, a defense analyst at the Lexington Institute.

But while acknowledging the danger is real, other experts such as Michael O’Hanlon of the Brookings Institute and Winslow Wheeler of the Center for Defense Information are not convinced that such an attack is imminent on the U.S. homeland.

Wheeler said that while UAVs have been used by terrorist groups such as Hezbollah and others with various degrees of effectiveness, he does not expect the threat of their use against the U.S. to be as prevalent as many believe.

“This actually makes non-state actors less effective since this increases their footprint and makes them easier to find,” said Wheeler. Suicide bombers are simply a far more effective weapon for such groups to use, because they can strike anywhere with little or no warning while needing little in the way of a support structure, he explained.

However, Richard Aboulafia, an aviation and defense analyst with the Teal Group, disagrees with this assessment.

Asymmetrical threat

“General aviation aircraft are the classic asymmetrical threat,” said Aboulafia.

According to Aboulafia, the most likely candidate aircraft for conversion into a drone or use as a weapons platform would be a light general-aviation aircraft such as a Cessna 172, which requires little support equipment; or an ultralight aircraft, which requires no infrastructure whatsoever.

Another potential new threat is the emerging generation of very light jets. These aircraft are small, relatively fast and require about the same level of support infrastructure as a piston-engine general aviation aircraft. The very light jets also use cruise missile-derived turbine engines, potentially violating the Missile Technology Control Regime treaty, said Aboulafia.

Converting such aircraft into drones is remarkably simple and can be accomplished using commonly available parts. Instructions to carry out such a modification are available on the Internet, said Aboulafia.

Previous attacks

Hezbollah used unmanned drones to attack an Israeli warship during the 2006 crisis and as long ago as Nov. 25, 1987 a Palestinian militant piloted an ultralight aircraft across the Lebanon-Israel border on to an Israeli army base and shot six Israeli soldiers dead before he was killed by return fire.

On March 26, 2007, the Tamil Tigers similarly used Czech-designed Zlin Z-143 light general aviation aircraft as bombers to strike against their government. However, Aboulafia thinks an attack using a business jet, while a genuine danger, is a far less likely threat due to the infrastructure and monetary requirements needed for such an endeavor.

While certainly a possibility, attacks on the U.S. homeland would be challenging due to geography, he said. The United States is separated by an ocean from Europe and the Middle East. Range and performance limitations inherent in the potential strike aircraft would necessitate attacks being launched from close to U.S. territory, if not from within the country itself.

However, attacks on U.S. and allied interests overseas are another matter.

“Drones are a real threat. It would be hard and relatively unlikely, though hardly impossible, for Hamas, Hezbollah or Al Qaeda to obtain and import such arms into the country and into position to attack, but there is a small chance they could,” said O’Hanlon. “But there is a very real chance they could do so overseas.”

Considering the fixed nature of U.S. installations, “It makes sense for non-state actors to use drones — they’re easy targets,” said Wheeler.

“Over the last 20 years we have shifted military competition to areas where less-developed countries and non-state actors can compete," said Thompson. "UAVs, network-centric warfare and special-operations forces are all areas where Hezbollah and al Qaeda can compete. The current trend in emphasizing irregular warfare makes it far easier for the competition.”

Countering this potential threat will be difficult because human intelligence is the only reliable way to prevent an attack, said Aboulafia.

Concurring with this view, O’Hanlon said, “At large bases or key facilities, air defenses together with aerial surveillance and monitoring could be needed. But in general it’s intelligence, plus controls on the movement of people and better inspection of cargo entering the country in the case of homeland security” that will be key to securing U.S. interests from a sneak aerial attack.

The threat should not be underestimated, warns Thompson. Organizations such as “Hezbollah have more options than many think in this area,” he said.