Terror on board - The 'system' — such as it is — didn't fail

"But did the "system" really fail?

To begin, airport security passenger screening is designed primarily to identify and prevent people from bringing weapons on board a plane to avoid another hijacking similar to Sept 11, 2001.

Metal detectors and X-ray machines are not intended to detect explosives. Just as hijackers brought box cutters on board on Sept. 11 - when airport security was then focused on guns - Mr. Abdulmutallab appears to have exploited a loophole. It's simply unrealistic to expect security to have detected the pentaerythritol tetranitrate (PETN) hidden on his body."