LONDON  The day after the deadly blast at Russia’s Domodedovo Airport, the impact in that country is being felt.   Metal detectors at the entrance of the arrivals hall are now in place.  A criminal investigation has been launched.  Terror is suspected.

“It was an accident waiting to happen,” Phil Baum editor of the London-based Aviation Security International told Fox News.

Most airport terminals are public spaces and an inviting target for the terrorist.

Still experts are not sure how much the attack will change global airport security.

“They have a very identifiable risk in Russia,” David Learmount of UK’s Flight International told us.

The other challenge is that, outside of customs, airports are difficult places to secure.   It is expensive and logistically difficult to check everyone coming into the arrivals hall.

And even if there are metal detectors at entrances, new lines and concentrations of people will build up elsewhere.

“All you’re doing is moving the target outside of the terminal,” Learmount noted.

What is more effective and practical, experts say, is screening, profiling and heading off potential terrorists by undercover police and others.

“It is basically a risk assessment of passengers,” aviation expert Baum noted, “how they behave and how they act is noted.”

The Transportation Security Administration does reportedly have some 3,000 “behavorial detection officers” at US airports.

Experts tell us, especially after Moscow, more of those, are needed.