Targeting airliners: aircraft missile defense: the debate continues.

• Author: Magnuson, Stew
• Position: HOMELAND DEFENSE

The threat is said to be out there: a terrorist uses a shoulder-fired missile to take down a U.S. commercial airliner.

With up to a million man-portable missiles produced since the 1970s, questions remain as to how much should be done to protect U.S. commercial airliners.

These weapons "are a threat that we have to take seriously," Homeland Security Secretary Michael Chertoff told reporters recently.

In the wake of 9/11, Congress mandated that the Department of Homeland Security research long-term and short-term solutions to the problem. And while there are sharp disagreements over what the solutions should be, if any, industry experts concur that the threat should not be underestimated.

Clifford Lewis, president and chief executive officer of the risk management firm, Strategy X Inc., said the question is how does the threat compare to other scenarios, such as a terrorist again using jets as a weapon of mass destruction.

"There is no historical precedent for anyone using a shoulder-fired weapon in the continental United States," he said. That doesn't mean it can't happen, or that a U.S. airliner won't come under attack while flying into a foreign airport, he added.

"Is the threat real? Is it possible to do it? Of course, it is," Lewis said. "But where does that rack and stack with all the other threats?"

Since the 1970s, weapon manufacturers have produced more than 700,000 shoulder-fired missiles, some of which have fallen into terrorist hands, according to a 2005 Rand Corp. report, "Protecting Commercial Aviation Against the Shoulder-Fired Missile."

A commonly used term for these missiles is MANPADS, or man-portable air defense systems. They are relatively simple to use, compact, and therefore, easy to smuggle. That, put together with terrorists' proclivity to target commercial aviation, makes them a real danger, according to experts.

The State Department estimates that approximately 20 countries produce the technology, and puts the number of MANPADS manufactured since the 1970s higher at 1 million. "Several thousand" shoulder-fired missiles are outside the control of governments, it added.

Countering the domestic threat falls to the State Department, which is charged with proliferation issues, and the Department of Homeland Security's Customs and Border Protection agency, which must stop loose missiles from entering the United States. If their efforts should fail, and a terrorist succeeds in taking down a commercial airliner, the cost...