With yet another plane crash on Monday in what is turning out to be a bad year for air accidents, aviation expert Clive Irving says the E.U.’s “ black list” of airlines should be given more credence.

We now learn that Yemen Airways, one of whose Airbus A310s crashed in the Comoros Islands Monday with 153 people on board, had been on the European Union’s watch list between July 2007 and the end of 2008 for “incomplete reporting” of inspections of its fleet.

If you want to check the safety record of airlines, it’s a good idea to think in terms of used cars. Like cars, older models get sold by their first-time buyers, and then pass down a chain of owners. These tend to be airlines who are glad to find a bargain. But as in cars, one obligation that comes with older models is that they need increasingly vigilant maintenance. Parts wear out, minor things fail. There is no reason why a modern airliner—certainly any up to 25 years old—can’t keep on trucking if it is well serviced and maintained. The trouble is, who is watching that they are?

The effectiveness of airline regulators reflects the culture of the country.

The European Union has the toughest screening process: More than 160 airlines are on its black list, meaning that they are not allowed to fly into or out of E.U. countries. In reacting to today’s crash, the E.U. transport commissioner, Antonio Tajani, proposed that this E.U. list be extended to a global black list. Good idea.

I’ve been trawling that list of 160. It includes companies registered in Kazakhstan, Sudan, Afghanistan, Rwanda, Angola, Benin, the Democratic Republic of Congo—you get the picture. More significantly, it also includes all carriers “certified by the authorities with responsibility for regulatory oversight” in Indonesia, which is hardly a Third World country, but which has a record of sloppy enforcement of safety standards.

The effectiveness of airline regulators reflects the culture of the country. Obviously, European and U.S. regulators have high technical standards and independence. In South America, aviation in Brazil is regulated by the military, in a professional way, but such oversight can be politicized and not as independent as it should be. Yemen, rife with tribal and sectarian conflict and a frequent victim of terrorism, hardly represents the kind of stable, conscientious regime that would guarantee reliable supervision of airlines.

This is turning out to be a very bad year for air accidents—an unusual anomaly after what had been a long period of improvement in the safety record. There is no common thread running through the crashes in 2009. The A310 involved in the Comoros crash is a first-generation Airbus, a design that has proved extremely reliable even though it is no longer built. It does not have state-of-the-art “fly-by-wire” cockpit automation and is, therefore, more vulnerable to being mishandled by pilots than modern Airbuses.

We don’t yet have a clear picture of what happened with this Airbus. But the general rule of thumb, that an airline at the end of the selling chain of used machines should be avoided, holds good here.

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Clive Irving is senior consulting editor at Condé Nast Traveler, specializing in aviation.