Terrorists planted two bombs on separate cargo planes. Despite the bombs being x-ray'd twice in one case, and at least once in the other case, and despite other typical measures (bomb sniffing machines) being in use at the loading facilities, the bombs were undetected. They were hidden in the printer cartridges of printers being shipped across the Atlantic.
Wikipedia indicates that the 300g and 400g amounts of explosives used (under a pound each) were enough to level a house. Significantly less could have been used to blow a hole in the airplane.
It was a toner cartridge for a laser printer - significantly larger than the inkjet cartridges you may be imagining.
Cargo plane bomb alert: explosive devices 'designed to harm US synagogues' - Telegraph
Turns out that in this case, human intelligence was required to detect the plot, and find and defuse the bombs (one only minutes prior to its intended detonation).
Wikipedia indicates that the 300g and 400g amounts of explosives used (under a pound each) were enough to level a house. Significantly less could have been used to blow a hole in the airplane.
I wonder, though, if the security measures for cargo planes are more lax than passenger aircraft? I expect that if they could have, they would rather blow up people than pilots and cargo.On 29 October 2010, in the al-Qaeda in the Arabian Peninsula 2010 cargo plane bomb plot, two PETN-filled printer cartridges were found at East Midlands Airport and in Dubai on flights bound for the United States. Both packages contained sophisticated, expertly constructed bombs concealed in computer printer cartridges filled with PETN.[40][41] The bomb found in England contained 400 grams (14 oz) of PETN (five times the amount needed to level a house), and the one found in Dubai contained 300 grams (11 oz) of PETN.[40] Hans Michels, professor of safety engineering at University College London, said that just 6 grams (0.2 oz) of PETN—around 50 times less than was used—would be enough to blow a hole in a metal plate twice the thickness of an aircraft's skin.[42] Intelligence agencies believed the packages were linked to al-Qaeda in the Arabian Peninsula, based in Yemen. The two suspect packages—confirmed by Home Secretary Theresa May as "viable" and "could have exploded"—were addressed to synagogues in Chicago. U.S. and U.K. officials believe the planes, and not the addressees, were the targets.[43] The packages found on the planes triggered alerts in the U.S., the U.K., and the Middle East. Frank Cilluffo, the director of the Homeland Security Policy Institute at George Washington University, said: "It is evident that had we not had the intelligence, our security countermeasures would not have identified these improvised explosive devices."[44] PETN is difficult to detect because it has a very low vapor pressure at room temperature, meaning very little of it gets into the air around the bomb, where it can be detected.[41] Qatar Airways said that "the explosives discovered [which it carried] were of a sophisticated nature whereby they could not be detected by X-ray screening or trained sniffer dogs", and were only discovered after an intelligence tip-off.[45][46][47][48] Both parcels were x-rayed in Sanaa, and the one in Dubai was x-rayed there, without the bombs being spotted.[49] The Bundeskriminalamt (BKA; the German Federal Criminal Police Office) received copies of the Dubai x-rays, and one BKA investigator said that German security staff would not have identified the bomb either.[49][50]
It was a toner cartridge for a laser printer - significantly larger than the inkjet cartridges you may be imagining.
Cargo plane bomb alert: explosive devices 'designed to harm US synagogues' - Telegraph
Turns out that in this case, human intelligence was required to detect the plot, and find and defuse the bombs (one only minutes prior to its intended detonation).