Originally Posted by
LarryJ
The AIT scanners purpose is to find non-metallic items which are concealed in, or under, a passengers clothes--something that the WTMD can not do. They'll also find metallic items as well. The threat of explosives, which would pass through the WTMD without any chance of detection, is what led to the adoption of the AIT scanners.
Back in 2010 there was a report based on an attempt to reconstruct how the AIT scanners worked that made two predictions:
1) Metallic objects held away from the body would be undetected.
2) Explosives that were feathered on the edges would be undetected. The scanner can't see thickness, only edges. Deny them the edge.
Since that time we have seen #1 demonstrated against the real machines. I see no reason to think they weren't just as accurate with #2.