Originally Posted by UAL_Rulez
They *make* it airside, probably (due to need for cooling baths) in a kitchen or catering facility. Then hand it to ticketed terrorist pax in bottles. Needs minimal or no ignition source, as you say - as I understand, chucking the bottle on the floor (say, at an overwing row - i.e. directly above the center wing fuel tank) should do it. As I understand TATP, looking at it wrong can cause it to explode.
If the concept is to put it in Gatorade bottles or the like, how are you going to stop those from coming aboard except to forbid all liquid containers in carry on bags?
If you're going to assume that the caterers can synthesize it airside and then hand it off, then you might as well shut down the airport. Other, less-volatile explosives could also be synthesized airside and will not be in liquid form. Moreover, they could be handed off to a terrorist pax who smuggles them onto the aircraft in his/her pants or butt.
Making explosives is really not all that difficult if one has the resources. If you're going to assume that the resources for TATP are airside and justify a liquids/gel ban, then you might as well insist that passengers fly naked, carry nothing, and have a colonoscopy before boarding. There are plenty of stable, solid explosives that can just as easily be synthesized airside, then smuggled on board or even walked on board in plain sight that will not be detected.