Integrated Security

Oct. 8, 2001

Integrated Security

SFO’s checked baggage inspection system raises the bar for screening

By Lindsay M. Hitch, Assistant Editor

October 2001


The RFID (radio frequency identification) tags in use at San Francisco’s International Terminal are provided by SCS Corporation, a manufacturer of RFID tags and scanners.
SFO is using the 2- x 2-in. self-adhesive Dura-label, attached to the standard baggage tag at the check-in counter. Bags can be passed through EDS screening without alerting passengers.
SCS RFID tags and scanners operate on a 2.45 GHz frequency with a 99.9 percent read rate. The RFID tags cost about $0.80 per tag.
For more information, visit

SAN FRANCISCO — The new International Terminal at San Francisco International Airport (SFO) features a system that provides 100 percent X-ray screening of all outbound international bags using RFID technology for routing selected bags through an Explosives Detection System (EDS). Installed in anticipation of future FAA security requirements, the checked baggage inspection system may soon become a necessity for other airports as well.

San Francisco’s new checked baggage inspection system (CBIS) exceeds current FAA requirements for checked baggage screening. SFO is the airport first in the country to provide 100 percent screening of checked bags on international flights. The CBIS was designed and installed in anticipation of future FAA checked baggage screening requirements, says Mark Denari, manager of aviation security and special systems for the airport.

Terminal Stats

• 2.5 million square feet
• 168 common-use ticket counters
• 24 wide-body gates
• BAE’s MagnaSort baggage handling system — 7 miles of conveyor belts
• 100 percent X-ray of all outbound international bags
• Ten two-dimensional Z-Scan-7 X-ray machines
• Four three-dimensional CTX-9000 EDS units
• Two baggage inspection rooms
• 300 bags per hour through EDS inspection
• 1,000 bags per hour through X-ray machines
• 2,720 - 3,400 checked bags over six one-hour departure periods

The checked baggage inspection system consists of up to four phases of screening, depending on bag selection and screening operator review.
All checked bags are routed through Stage 1, an automated X-ray machine that either accepts bags for loading or rejects them, sending them on to Stage 2.
Stage 2 allows trained operators to review the images produced in the Stage 1 X-ray machine. If cleared, the bags are routed for loading. If operators need further clarification, the bags are routed to Stage 3.
Stage 3 passes bags through an FAA-certified Explosives Detection System. The EDS machine scans bags for compounds matching the density of known explosives. Operators either send the bags to the aircraft or to Stage 4.
Stage 4 physical inspections are conducted in the Baggage Inspection Room. The exterior of bags are screened using an Explosives Trace Detection system. If bags reach Stage 4, the bag’s owner is paged and escorted to the Baggage Inspection Room by an airline or airport employee. Once the owner is present, the bag may be opened and physically searched.

Bags are routed through the system using a small RFID (radio frequency identification) chip attached to the standard baggage tag. A scanner at the ticket check-in counter encodes the RFID tag with specific data relating to the flight and selection for EDS screening.
Bags selected for screening at the ticket counter receive special encoding on their RFID tags. The bags pass through Stage 1 as usual, and Stage 2 as necessary. Then, regardless of the determinations of Stages 1 and 2, the bags pass through Stage 3 EDS screening.
An RFID antenna array interrogates bags as they leave Stages 1 and 2. Those with encoded RFID chips "reflect" data to the antenna, directing the system to transport selected bags through the EDS equipment.
The baggage handling control system is able to detect uncleared bags on "cleared" routes. Using hand scanners, employees can double-check clearance and remove the "stop load" message from the tag or reroute the bag as necessary.

The checked baggage inspection system took about five years from planning to design to installation, says Micheal Robert, security supervisor and FAA liaison for SFO. The system cost approximately $10 million, $4.4 million of which was covered by federal AIP funding.
Robert reports that system testing is now complete, having run from November 2000 to May 2001. CBIS is now fully operational and continues to undergo minor component refinements.
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