Explosives can be hidden in devices, liquids

Even then, baby formula was excluded from the ban — even though, in powdered form, it can provide a good vehicle for masking crystallized explosives.

A decade later in Belfast, Northern Ireland, an Algerian man was convicted of possessing 25 computer disks detailing how to bring down an aircraft using, among other things, crystallized explosives hidden in a container of talcum powder.

During that trial, FBI explosives expert Donald Sachtleben testified he built and detonated three bombs based on the instructions found in the Algerian’s home.

Despite this decade-old knowledge, airport security officials around the globe still permit passengers to carry a wide range of containers onto planes without any visual inspection.
The increasing probability that terrorists will try to strike with explosive components hidden in hand-luggage has been accompanied by a trend among some discount airlines to encourage passengers to rely more on carry-on baggage.

In recent months Europe’s market-leading airline, Irish budget carrier Ryanair, has imposed a mandatory charge on all check-in luggage. An Irish competitor, Aer Lingus, has announced plans to follow suit.

“I’m really surprised the Irish aviation authority hasn’t stepped in to moderate this rush to hand luggage by airlines,” said aviation expert Gerry Byrne. “All our airport security has been geared towards baggage going into the hold. ... It will overwhelm security if the emphasis is suddenly switched to (relying on) hand baggage.”

A British security expert, Steve Park, said a likely terrorist scenario would involve a two- or three-member team boarding the same flight, each carrying a different part of the planned bomb.

“They could combine resources on the plane. That would be perfectly possible on a busy flight,” he said.

Critical to conventional bombs is a power source to trigger a detonator. Clonan said cell phones could provide an ideal power-timer unit for a bomb.

“In mid-flight you could go into the toilet, attach the mobile phone to the explosives and, as the plane makes a final approach over a densely populated urban area, you detonate it,” he said.

To puncture an aircraft’s fuselage would require an explosive charge “half the size of a cigarette packet,” he said.

Hatcher said “liquid bombs” were not the most likely explosive. He said it was far more likely a terror cell would try to smuggle on an explosive in crystalline or powder form and to combine it with an acid-based compound.

Slide show   Air travel snarled by terror plot European and U.S. travelers face increased airport security after discovery of a British terror plot.

Hatcher said terrorists might also construct an on-board incendiary bomb based on paraffin or gasoline, which if ignited in mid-Atlantic could destroy an aircraft before it could land.

None of these items, he noted, can be detected by a typical $5 million X-ray machine used to scan luggage.

Hands-on inspection is the only way to tell if a dark-plastic medicine vial really contains what it says on the label.

“You’ll have to carry your prescription and prove to security that the medicine really is what it is. But for 20 million people a year going through Heathrow? How do you do that?” Hatcher said, foreseeing a future airport arrivals hall with five-hour security checks.

Even that scenario, he said, could lead to terror attacks — detonating bombs in an airport terminal, not on a plane.

“You can carry a bag into the center of an airport with thousands of people around you before you are ever screened. That, too, must change,” he said.

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