Here's what I'd do: Let's draw up a big list of dodgy airlines. Better, let's use rules; ex-Soviet aircraft, or old 737s, based in the UAE, registration in certain West African, Balkan, or Central Asian states, routes mostly to Middle Eastern and African destinations, and (especially) aircraft bought from or sold to other airlines in the list. We could implement it in software quite easily, at least to provide a filtered list for humans to review.
And then, whenever they land anywhere with trustworthy civil authorities, let's invoke the long-standing right of any landside state under the Chicago Convention to do an immediate safety inspection, a ramp check as they say in the trade. Naturally, quite apart from crawling over the plane with feeler gauges, that will involve checking all the documents; the manifest, the tech log, the ops manual, the QRH, the pilots' licences and log books, the air waybills for everything on the manifest, the aircraft registration documents... And, of course, whilst we're at it there's no reason why Customs and Immigration shouldn't search the hold.
If anything is out of order, we'll ground the plane; if anything is really bad, we'll seize it; if anything is outright criminal...yes. It may sound a bit hopeful, but consider some of the blog's back pages. We've seen UN-11007 hurtle off the runway in Riyan, officially full of fish but they burned all too well; the An-12 was registered in Kazakhstan to Air Bas, operating from Sharjah, but was working under yet a third and unknown AOC, that of "RPK" - a company which doesn't seem to exist. In Sudan, an Ilyushin-76 crashed working for Jet Line International, registered to Aerocom, on lease to East-West Cargo. One of the old Irbis Il-18s was grounded in Pakistan after a terrifying flight, several times overloaded with passengers, during which one of the pilots passed out with hypoxia.
It seems to be a defining condition of arms traffickers in the air that the aircraft make sense from one angle, usually that of the UAE authorities; as soon as you look at the details the whole picture dissolves. Here's another example:
During a ramp check in Beirut, it was discovered that the aircraft's operating documentation was split among all these firms; the insurance policy applied to a different plane, the tech log was from Ariana, the MEL (the list of the minimum equipment required for safe operation) was the American Airlines one, later replaced by a Swazi one that hadn't been approved by the Swazi authorities. These institutional flaws complemented a long list of physical ones. None of this should be surprising; UTA's chief pilot wasn't qualified on the B727 and neither was anyone else there. The tech manager was trained on the Lockheed Tristar and DC8, and the strong impression is given that literally no management structure for 727 operations existed...So, I'm delighted to see this report from SIPRI, always sound on the issue right back to the 90s, which suggests exactly that. You can get it here. Of course, being a bunch of Swedes or at least in Sweden, they're a lot more serious than me - they've got studies an stuff and tables and data. But don't take my word for it. Read the whole thing
Now, the same people are trying to get a change in European Union regs through the European Parliament to make this job easier. You might want to tell your MEP about it, especially if they're a member of ALDE - the European Liberals.
Update: Here's a specific talking point.
Lobby for, and support amendments and mechanisms by the relevant EU actors: European Commission DGs, the European Council, the European Parliament and concerned member states “to formulate and implement effective measures using existing EU instruments and regulations that will further reduce the number of air cargo and maritime companies involved in destabilising or illicit small arms shipments to Africa”.