Just two hours after air traffic controllers finished lambasting federal authorities yesterday for leaving the New York region’s major airports off a list to get new radar technology, the Federal Aviation Administration in Washington made a surprising announcement: New York was suddenly back on the list.

Reversing course, the FAA said Kennedy, La Guardia, and Newark Liberty airports would be among the first to be fitted for a state-of-the-art system designed to help prevent runway collisions.

The agency’s early afternoon announcement was news to the controllers, who first learned about the change from reporters after holding their own press conference at Kennedy Airport.

“We’re satisfied that they’re announcing that they’re doing something, but it’s sad that we didn’t hear it from them,” a representative of Newark Liberty International Airport’s air traffic controllers’ union, Russ Halleran, said.

The technology, called Airport Surface Detection Equipment Model X, or ASDE-X, detects movement on runways and taxiways by creating a continuously updated map of all ground operations at an airport. Most importantly, officials say, ASDE-X is an improvement over the existing system because it works in bad weather.

“It would definitely enhance the safety by 99%,” Mr. Halleran said.

Air traffic controllers at the New York airports have been calling for the new system since July, when a DC-8 cargo plane missed colliding with a Israir Airlines Boeing 767 by less than 100 feet on a rainy, foggy night. The Israir jet was carrying 262 passengers and had wandered undetected onto the cargo plane’s runway.

The FAA ruled the near miss was the result of a crew error, but the air traffic controllers blamed a faulty radar system that doesn’t work in bad weather. “It actually mistakes the rain for a plane,” the president of the controllers’ union at Kennedy, Barrett Byrnes, said of the current system, which was introduced in 2000. Inclement weather “basically renders it useless.”

An FAA spokesman, Arlene Salac-Murray, said yesterday’s announcement was not timed to coincide with the air traffic controllers’ news conference. The decision was “several months in coming,” she said.

Ms. Salac-Murray said the agency had begun testing the ASDE-X system in 2003 at airports in Houston, Milwaukee, Providence, R.I., and Orlando, Fla. “We have fielded ASDE-X at several smaller airports, with great success,” she said. Based on the results, Ms. Salac-Murray said, the FAA then decided to expand “to the busiest, high-density airports.”

She said it would cost a total of $27.5 million to outfit each of the region’s three airports.

Fourteen major airports will receive the first deployment of the new technology, the agency said, including those in Boston, Chicago, Los Angeles, and Washington. Seattle Tacoma International Airport will get it initially, in January, and the FAA hopes to install ASDE-X in 35 airports by 2011.

There is “no firm date” for when the three New York area airports would be fitted, and Ms. Salac-Murray said she did not know where they stood on the list.

Mr. Byrnes said he was skeptical at the shift in dates, noting that the FAA had originally planned to finish installing ASDE-X in the first wave of airports by 2009. He likened it to someone saying they were giving you a flatscreen TV, and then adding, “You’re not going to get it for about 12 years.”

“A lot of people can lose their lives between now and 2011,” Mr. Byrnes said.