Aviation security may be altering, warns MIT Sloan professor

CAMBRIDGE, Mass., Feb. 10, 2003 — Aviation remains a favored weapon of terrorists, but airline security has been compromised by the elimination of some security measures put in place after 9/11, and a passenger screening system set to be implemented this summer is fraught with controversy and risks, according to an MIT Sloan expert on aviation safety.

“Terrorists have long been fascinated by aviation, and I'm afraid it's just a matter of time until we have another incident,” said Prof. Arnold Barnett, who once headed an FAA research team to investigate anti-terrorist measures. “It could be a very short time or a long time. But as I look at measures that have been abolished (at American airports) and the risky character of some proposed new measures, I find myself more concerned than I was a year ago.”

Barnett, who uses statistical techniques to analyze policy issues, found that several efficient and low-cost security measures have been eliminated “My great concern is that security decisions are being made through a process that is not fully rational. We may be pulling away from quiet and cost-effective measures that have succeeded in favor of measures that are creating great bitterness and controversy and may achieve nothing.”

For example, Barnett, whose degree is in mathematics, ran cost-benefit analyses of two post-9/11 security measures identification checks at boarding gates and the asking of two simple questions to all passengers checking in for US domestic flights and concluded that their elimination made neither security nor financial sense. At the same time, changes proposed for the federal Transportation Security Administration's (TSA) Computer-Assisted Passenger Prescreening System (CAPPS) may wind up increasing the chance that terrorists could slip through, he said.

Like the current system, the new system, dubbed CAPPS II, would divide passengers into higher risk and lower risk groups. CAPPS II would use personal and demographic data to select higher risk passengers for more intense scrutiny “Such ‘data mining technology’ has limits, said Barnett, noting that the approach failed terribly in the Washington sniper crisis. And under pressure from civil liberties groups and others, TSA has stressed that very few passengers will be classified as potentially suspicious. TSA now says that perhaps 97 percent of all passengers will likely be classified “green,” meriting only a cursory inspection. And that, said Barnett, is playing with fire.

“Terrorists will be able to do trial runs, as the 9/11 people apparently did,” he said. “You can find out if you're the kind of person who gets scrutiny or not. A terrorist classified ‘green’ under CAPPS II might get less intense screening than someone classified ‘green’ under the present CAPPS I system, which TSA trusts less. We might end up at greater rather than lesser risk.”

The abolition of earlier security measures makes Barnett even more nervous about the implementation of TSA's new screening system.

The justification for eliminating gate checks, for example, was that they were superfluous since everyone boarding a plane had already shown their identification. But passengers might have intentionally or inadvertently slipped through such earlier checks, Barnett said. In any case, gate checks added virtually no cost to airlines or the government. “With zero cost, the measure would pass a cost-benefit test even if there were only an infinitesimal chance that it would some day stop a terrorist act,” Barnett said.

Similarly, Barnett said asking passengers two questions — Has anyone unknown to you given you something that you are bringing aboard the aircraft? and Has your luggage been in your possession at all times since you packed it? involved minimal costs against possible benefits. Using industry and FAA data, such as how much flight delays “cost” passengers, Barnett found that the monetary cost equivalent of asking these security questions was about $200 million a year, while a conservative estimate of the benefit of averting a terrorist attack on a US airplane is $5 billion.

“The two-questions policy would be cost-effective if it prevented one U.S. terrorist disaster over the next 25 years,” Barnett said. “Put another way, the policy would be cost effective if it stopped one of the next 12 billion domestic passengers from unintentionally bringing something aboard a plane that caused a crash.” He noted that a nine-year old boy recently tried to bring a teddy bear that he had received from a stranger onto an aircraft. It contained a loaded gun.

Barnett criticized another TSA decision to end the requirement that no passenger baggage can be loaded onto a plane unless its owner was also proven to be on board. While TSA claims that explosives screening of baggage eliminated the need for the luggage check, Barnett said the explosives detection was not perfect and that “bag match” added another layer of security, also at minimal cost.

“It would be terrible if an airplane fell out of the sky for any reason, but especially tragic if it was because of a security measure TSA had abolished,” Barnett said.

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