A federal judge here blocked the Federal Aviation Administration yesterday from transferring two of its divisions from Washington to Atlantic City after the 35 affected workers charged that they were singled out for the shift because they are older employes who might retire rather than move.

U.S. District Judge Harold H greene said the FAA "has not demonstrated that its decision was based on reasonable factors other than age" and that there is "at least a substantial likelihood" that the workers will be able to prove their age discrimition claims when the case goes to trial.

Greene granted the worker's request for a preliminary injuction blocking the scheduled Aug. 12 move, but said the FAA could allow individual workers who prefer to transfer to the Atlantic City facility to do so.

But the judge said that if the workers prove their claims that they were singled out for the transfer because of their ages, they will be entitled to collect damages under provisions of the Age Discrimination in Employment Act.

The worker's lawyer, Harvey M. Katz, said Greene's ruling was the first time a judge has ever blocked a federal agency shift on age discrimination grounds.

The 35 workers are GS-14 and GS-15 civil servants in the FAA's airport planning and aircraft safety and noise abatement division. Most of them are in their late 40s and older.

The FAA said that the average ages of the 95 workers in the two divisions are 48 and 49, but Greene noted that the averages were "distorted and in a sense equalized by the inclusion of secretaries and clerical personnel who are presumably younger and are not required to transfer to Atlantic City."

The FAA has claimed that the move of the two divisions, part of the agency's Systems Research and Development Service, is necessary because the two divisions' work is related to that done at the FAA's National Aviation Facilities Experimental Center a testing plant for airport equipment.

But the workers claimed in their suit that there are other FAA divisions that actually work more closely with the New Jersey facility than the two singled out for the transfer.

They also noted that last year the FAA announced plans to pare its work force by some 30 workers and suggested when the transfer was announced that the affected workers may want to retire rather than go to Atantic City.

The FAA's "efforts to controvert [the workers'] allegations are thus far largely unconvincing," Greene said.

The four workers who filled the suit Stephen A. Cannistra, 64, Frederick Horn, 53, Cole H. Morrow, 67, and Hisao Tomita, 48 -- said in their complaint that "older people would find a move to Altantic City, which accurately or not has been characterized by the media as the new vice capital of the nation, as particularly distasteful." They said they did not want to uproot and lose their friends and contacts they had made over a period of years in Washington.

Assistant U.S. Attorney David H. Shapiro, who represented the FAA in the case, refuse comment on the ruling.