Nearly five years after the 9/11 Commission Act recommended that 100 percent of cargo aboard passenger planes be screened, The Transportation Security Administration has announced a deadline to meet the requirement.

TSA on Wednesday set Dec. 3, 2012, as the mark for carriers to conduct full cargo screening on international flights bound for the United States. As of that date, all cargo on international flights must undergo screening for explosives, TSA said in a press release.

The system adds additional “risk-based, intelligence-driven procedures,” before items are shipped and “enhanced screening” for shipments designated at a higher risk, TSA said.

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“Harmonizing security efforts with our international and industry partners is a vital step in securing the global supply chain,” TSA Administrator John S. Pistole said in a news release announcing the deadline. “By making greater use of intelligence, TSA can strengthen screening processes and ensure the screening of all cargo shipments without impeding the flow of commerce.”

Air carriers often transport commercial items in their jets' cargo holds. On larger planes, numerous containers sealed by the shipper -- roughly the size of a Volkswagen beetle -- fill up the space.

Douglas R. Laird, president of Laird & Associates, Inc., an aviation security consulting firm, says just because 100 percent of cargo is screened doesn’t mean that nothing could slip through detection.

“That sounds good on its face, but there really is no good technology to fully screen some of the larger cargo, like containers,” Laird told msnbc.com, noting that the newest computerized machines are good at sniffing out potential explosives in suitcases and packages, but aren't useful on such cargo as containers and and other big items like high-end cars that end up on airplanes.  

Risk-based intelligence, he explained, is essentially profiling the shipper to determine whether that company or individual poses a potential risk. A terrorist, however, could try to target a shipping company by getting a job there.

“Everyone want’s 100 percent, but the only problem is there is no such thing as 100 percent,” he said.

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