TSA spokesperson Sterling Payne responded by email. "While there is no silver bullet technology, advanced imaging technology is very effective at detecting metallic and nonmetallic threats on passengers, including explosives," said Payne. "Further, this technology doesn't stand alone: It's one part of our multi-layered strategy to minimize risk, deter future attacks and protect the traveling public."TSA began piloting imaging technology in early 2007," said Payne. "Through the pilot process, TSA gained operational information used to enhance training, improve the screening process and further bolster detection capabilities. Using this critical technology, TSA routinely detects artfully concealed metallic and nonmetallic prohibited items. TSA completed comprehensive operational testing and evaluation of this technology and is confident that it will significantly increase our detection capability at the checkpoint."
Payne said the AIT scanners cost between $130,000 and $170,000 per unit. That means deploying the full 1,800 will cost taxpayers between $2.34 billion and $3.06 billion.
And even if they could be counted on to detect an underwear bomb, the TSA, after buying 1,800 of them, intends to leave 500 domestic airport security checkpoints without them.
"There's about, from my understanding, 2,300 checkpoints," Lord told the Senate subcommittee last week. "So if you acquire 1,800 machines, it's still not going to be enough to ensure 100 percent coverage. TSA's strategy is to focus the use of these machines on the highest-volume airports."
Whether in fact a whole-body-image scanner catches a future underwear bomber boarding a flight in a foreign airport will depend not only on the effectiveness of the scanner, but on the country in which the airport is located. "At least 13 other nations are now testing or deploying these scanners, or have committed to deploying them in the near future," Lord told the Senate subcommittee.