The bag is tagged and placed on a conveyor belt, which carries it behind the counter. Electronic photo “eyes” on each segment of belt will track the bag’s progress throughout the process. 1. COUNTER OR CURBSIDE Large items such as bicycles are separated from the start. But some items that make it onto the belt won’t fit properly in the screening machine. They are sent to the physical examination area. 2. WEEDING OUT MISFITS Each bag is CAT-scanned and its contents evaluated electronically as it moves through an explosive detection system (EDS). Each machine — the Delta terminal has three — can screen up to 500 bags per hour. If the machine is not sure about a bag or detects something that requires a closer look, the bag will be diverted to a secondary belt. 3. SCREENING FOR EXPLOSIVES 4. TSA TAKES A PEEK More than 95 percent of bags are cleared electronically and are not touched until they are loaded by baggage handlers onto carts that carry them to their planes. 7. CLEARED FOR TAKEOFF If at any point an explosive is detected, a team of TSA bomb specialists is called, and police may be summoned as well. Police are alerted if TSA officers find large amounts of cash, drugs or undeclared weapons while looking for explosives. 6. BOMB TEAM MAY BE CALLED If the officer sees a problem or can’t tell what an item is, the bag is taken off the belt. A TSA technician swabs it for traces of explosives, then opens it. The scanned image on a monitor shows where the suspicious content is. It takes about two minutes to inspect a bag. Once the officer is satisfied that the bag contains no threat, he repacks it and inserts a note saying the bag was searched, and the bag goes back on the belt toward its plane. 5. PHYSICAL INSPECTION If the bag is diverted, a TSA officer in a nearby room will look at its scanned image. The 3-D image can be rotated for a 360-degree view of the bag’s contents. This usually takes three to four seconds per bag. If the officer clears the bag, it rejoins the main belt and goes to its plane. Most items that trigger the EDS are benign.

SOURCE: David Marzola, assistant federal security director for screening; Kristin Katz, Transportation Security Administration stakeholder liaison; L3 Communications. GRAPHIC: Bonnie Berkowitz and Alberto Cuadra - The Washington Post.