WASHINGTON - An airplane could be blown out of the sky by a cigarette-pack-sized bomb hidden in a cargo hold or a small, plastic bag of explosives tucked inside a passenger's clothes.
Those scenarios - and others - are among the many concerns expressed by aviation-security experts and lawmakers who say gaping holes remain in the nation's security net despite myriad improvements since the Sept. 11 attacks.
Their interest became more intense last month when airline employees in Orlando smuggled a duffel bag full of guns and drugs onto a Delta flight to Puerto Rico.
Since the March 5 incident, lawmakers on Capitol Hill have proposed more laws to protect airline passengers. In addition, Orlando International Airport and the Transportation Security Administration quickly beefed up screening of airline and federal airport employees.
But there's pressure to do much more. Among the weaknesses identified in the nation's current system:
Screeners have no technology to detect whether passengers walking through a checkpoint have liquid explosives hidden on them.
All checked bags are screened for explosives. But the most effective way of screening is expensive, so only a few airports employ it. Others airports use technology that critics say is largely ineffective.
The vast majority of the cargo loaded onto passenger planes is not screened.
Thousands of airport, airline and vendor employees throughout the country duck in and out of secure areas by simply flashing their badges instead of going through screening. That loophole allowed two Comair employees at Orlando International to sneak an assault rifle and 13 handguns onto a Delta Air Lines flight to Puerto Rico, leading to renewed uproar over passenger safety.
Major changes in airline security followed the Sept. 11 attacks, in which terrorists brought down four airliners and killed nearly 3,000 people.
All checked bags were ordered screened for explosives. Cockpit doors were made impregnable. The air-marshal program was beefed up considerably. Some pilots were given permission to carry guns. The screener work force was federalized and trained better. Terrorist watch lists were expanded. And items that passengers can bring aboard were limited.
After Richard Reid tried to light a bomb in his shoe during a flight, new rules were added to screen footwear as well. And after a plot was uncovered last summer to bomb flights between England and the U.S., liquids in carry-on bags were limited.
But aviation-security experts say all the reactions focus too much on past incidents and not on what innovative attack might come next.
"I have a great concern about the system's ability to be able to even detect an attack, which I greatly fear is in the planning stages," said Rep. John Mica of Florida, the top Republican on the House Transportation Committee.
Mica's biggest fear is "clean terrorists and clean bombs," meaning attacks by people who don't fit traditional terrorist profiles using easily available materials that can evade current bomb detection.
"If terrorists were to light up a neon sign in front of the Capitol and give us a hint what they're doing, they couldn't be any clearer. The next one will be a clean bomb," said Mica, who has access to classified briefings. "There's nothing in place that will prevent that."
David Heyman, director of homeland security at the Center for Strategic and International Studies think tank, said liquid explosives have been a threat since long before Sept. 11, notably the 1995 "Bojinka" plot to blow multiple jetliners out of the sky. But it took the discovery of a new plot in Britain to bring about rules limiting the liquids that passengers bring on board, he said.
There are no security checkpoints that can detect hidden liquids on passengers.
A body-scanning machine that shows screeners an X-ray-type image of people is being tested in Phoenix. It shows a picture that could detect hidden liquids, but it also has raised concerns about privacy.
Douglas Laird, an aviation consultant and former security director for Northwest Airlines, said such technology is imperative. "It doesn't take much to cause enough of an explosion to create a hole large enough in the plane that the plane blows itself up because of the pressure difference," he said.
Security consultant Larry Johnson of BERG Associates, a former CIA and State Department official, said Congress has not put enough money into developing new technology for screening people and bags.
"They have not made it a priority. There has not been the equivalent of a Manhattan Project," Johnson said. "It's considered so unlikely, they think they can get away with doing nothing."
It's not cheap. Johnson estimated that developing a passenger-screening machine that can detect explosives would cost $3 billion.
Meanwhile, TSA spokesman Christopher White said the agency does have ways of detecting explosives on individuals, including behavioral training. "We have learned over the past five years that a flexible, unpredictable approach to aviation security is the best approach," White said.
Mica, former chairman of the House Aviation Subcommittee, said he has set aside millions for research and development in past budgets only to see it diverted to other uses. Several years ago Mica proposed increasing ticket taxes to quickly buy the best equipment for screening checked bags, but airlines and airports opposed the idea.
The problem with checked bags is a shortage of the best explosive-detection machines. Congress hasn't spent enough to place those in all airports, so most airports use trace-detection technology, Laird said.
Trace-detection machines - many equipped with wands that pick up on explosive residue - cannot always find liquid explosives in checked luggage if someone packages the explosives correctly.
"A dog can play with it and not know it's an explosive," it's so well-disguised, Laird said.
Mica has pushed for conveyor-belt "in-line" explosive-detection machines that are much more accurate. Classified and other spot checks of the trace-detection system show it fails to find explosives, he said. "If the results were revealed to the public, they would demand immediate action."
The Transportation Security Administration, which handles screening, has a plan to put the in-line systems into the 250 airports with the most baggage. But under current funding levels of $22.4 billion during 20 years, it would take until 2024 to get them all installed. Mica said Orlando is looking for funding for a $120 million project to upgrade to the in-line bag screening. Airports in Tampa and Jacksonville have switched to the better technology already, he said.
Several pieces of legislation propose screening all cargo that goes onto passenger planes. One of those bills would increase the percentage of cargo screened to 35 percent by Sept. 30 and to 100 percent two years later, which TSA has said is not possible.
In addition to the current random cargo screening of a small portion of shipments, TSA has a system to check the companies that handle the cargo and focus on higher-risk shipments.
"It's almost comical you make such a big deal about what a passenger has in their take-on baggage, yet we're not making a big deal of cargo," said Richard Bloom, director of terrorism, intelligence and security studies at Embry-Riddle Aeronautical University, which has campuses in Florida as well as Arizona.
But Laird, a former Secret Service agent, doesn't think terrorists would use cargo for an attack. Cargo sometimes gets rerouted onto trucks, so it's not predictable for terrorists.
But Johnson said cargo ought to be left off passenger planes until a better screening system is developed.
The Orlando arrests have spurred cries for screening all workers with access to secure areas of the airport. Rep. Ginny Brown-Waite, R-Fla., pushed the idea in legislation that will come before the Homeland Security Committee on April 24. Her bill would set up pilot programs to screen all workers with access to secure areas at five large airports.
But Bloom, who spent 20 years working for military and civilian government intelligence and security agencies, said screening all workers is not the answer.
"The more you pay to screen everybody, the less you have" for other important security measures, Bloom said.
Bloom and other experts say security always will involve trade-offs. Good security involves looking at the threats and vulnerabilities at each airport and tailor-making a defense system. He favors fewer national mandates from Congress and more ability for local airport-security chiefs to adapt to changing risks and focus on worst-case scenarios.
"Even if you had the entire federal budget, you wouldn't have a perfect system at Orlando," he said. "There are an infinite amount of vulnerabilities."
Distributed by McClatchy-Tribune Information Services.
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