David Frum at FrumForum has a post up that examines who the real culprit might be in the failed terror bombing on Christmas Day. while I agree with David on the points he makes about the breakdowns that allowed the terrorists to fly I must disagree with him on screening for bombs.

Airline terrorism is a complex problem not a simplex one, and we cannot guarantee that the next bomber will be on any lists or known to any intelligence agency; therefore we must also examine how a PETN bomb made it through at least two security checkpoints before arriving in the US where by sheer luck it failed to detonate properly. So David is missing point number four: we must have layered defenses — both bombs and terrorists must be screened for.

There’s going to be a lot of political flaming over this incident, and I’m going to forgo that. Blame can be layered in large quantities on both parties for this one and I fully expect large Federal agencies to have their failings: it’s the nature of the beast. Instead I will focus on what we should do to prevent the next attempt, without focusing on the human and agency failures since that will be examined in detail across the political spectrum and in most other media.

The ways we search for bombs now does not work for flights arriving from overseas airports. That’s evident from this attack and others. There are several high tech and low tech means to detect explosives and other threats, but as usual this boils down to bureaucracy just as the problems David examined did, and the cold calculus of risk vs. costs.

While some airports have functional “puffer machines” that can detect chemical signatures of explosives, they are highly expensive (160K,) too slow to use for every passenger in busy airports, and also take a lot of care and feeding from techs. The costs preclude them from being in airports like the one in Nigeria that the bomber originated at.

Dogs are able to detect trace amounts of explosives and are able to pick up those signatures from mines buried underground for decades in Afghanistan. That’s low tech, but it works. I have no doubt that had the terrorist passed within ten feet of such a dog that he would not have flown. Other animals and even insects can also be trained to detect the most common explosives (C4, PETN, etc,) and they can be tastefully concealed behind grills.

Another method would be full body scanners which is being proposed and which the Nigerian airport will start using. Privacy advocates and religious fundamentalists might object to these – however they appear to be a necessary evil in this day and age. As more of these come into use in a couple of years economies of scale should decrease the price and make them as common as metal detector small airports now. Like metal detectors full body scanners will only be at the security gates which leaves a security gap.

A concern that I have about airports is that a bomb in a crowded airport can be just as dangerous as bomb on a plane; the terror attack with a car bomb in Glasgow demonstrates that the terrorists are well aware of the potential for mass casualties in any given airport, or for that matter any transport nexus or place where many people gather.

We need systems that detect the most common explosives quickly, cheaply, and as efficiently as the common smoke detectors in your home work to detect fires and carbon dioxide. There’s a lot of money to be made for the first manufacturers who comes up with  explosives detectors designed not to detect explosives on a particular person but rather detectors that sense in general whether explosives are in an area and then send an alarm. Put these at every door of every airport, and you have a way to alert security that explosives have entered the airport. If you can’t do that go low tech and use dogs. The best solution would be layered and would use dogs, mechanical detectors at doors, and the full body scanners. I suggest some people get working on that since there is a lot of money to be made.