Bowing to the threat of a cutoff of $3.7 million in federal housing aid, the Fairfax County Board of Supervisors rescinded yesterday its stand against construction of a controversial public housing project in Springfield.

The supervisors did not endore the 100-unit, subsidized Rolling Road Estates project, but by voting 5 to 2 to drop their opposition to it, they effectively approved it. Two other supervisors abstained on the vote.

The board's action lets stand a decision by the county housing and community development department to approve construction of the project between the Newington Station and Saratoga subdivisions. The project must still be approved by the Virginia Housing Development Authority.

The board acted after receiving a letter last Friday from the U.S. Department of Housing and Urban Development saying that the board' opposition to Rolling Road Estates joepardized the $3.7 million that the county receives each year from HUD in community block grant funds.

"I don't like the idea of HUD threatening us, but this is a reality of life," Supervisor Alan H. Magazine (D-Mason) said of the letter from the Washington area HUD office. "There's no question that we fall short in our share of public housing, or HUD would not have reacted the way it did. There are conditions you have to accept when you take federal funds."

"The board's action was a real setback," said Alvin Smuzynski, a resident of Saratoga subdivision and leader of nearby residents opposing construction of Rolling Road Estates. "But we still have time to present our case against the project to the state (authority) and to HUD, which has to give final approval to Rolling Road. The fight's not over, that's for sure."

Residents of Saratoga, Newington Station and Chancellor Farms subdivisions have been fighting Rolling Road Estates since learning in September that it was well on the way to being these communities base signed petitions against the project in the past two months.

The project would contain 70 townhouses for moderate-income families and 30 units for two-income families. A family of four with a maximum income of $10,500 would qualify for the low-income housing, while a family of four with a maximum income of $16,400 would be eligible for the moderate-income housing. "We're talking about teachers, firemen and policemen who need housing like this to be available in the county," said Magazine, who voted to overturn the board's opposition. "We're not talking about a blight in the community."

Supervisor Marie B. Travesky (R-Springfield), who opposes the project, said the county staff's approval was based on "erroneous information that appears to be the same information on which HUD is basing its opinion." She said HUD "must be made aware of the inaccurate assessment" made of the proposed location "as a good one for a public housing project." She said the community does not have adequate facilities nearby for public housing.

Board Chairman John F. Herrity, who also opposes the project, called HUD's letter "an attack on the ability of a local government to make decisions on a local level affecting local citizens." He has said before that the Springfield area is in danger of becoming the "public housing capital of Fairfax County."

Herrity charged that Rolling Road Estates was developed "under an aura of secrecy" and said he plans to meet with Gov. Mills E. Godwin and the state housing on the issue.

Supervisor James AM. Scott (D-Providence), a long-time supporter of low - and moderate-income housing in Fairfax, are only 36 public housing units out of 3,100 housing units within a two-mile radius of the proposed location for Rolling Road Estates.

Voting with Scott and Magazine to rescind the board's opposition to Rolling Road Estates were Suprevisors Martha V. Pennino (D-Centreville), John P. Shacochis (R-Dranesville) and Warren I. Cikins (D-Mount Vernon).

Supervisors Joseph Alexander (D-Lee) and Audrey Moore (D-Annandale) abstained on the vote.

The board also declined to deal with another politically controversial topic - abortion.

About 35 anti-abortion supporters carrying plastic red roses of a proposal to use Fairfax funds to pay for elective Medicard abortions.

"If as a taxpayer I am forced to pay for something I believe to be killing human life, that is taking away my freedom to practice my religion," said Louise Hunt of Annandale, a member of the Virginia Right to Life anti-abortion organization.

The turnout of abortion foes was prompted by a request from the county's social services board asking the supervisors to decide whether to use local funds to finance elective abortions for women who cannot afford to pay for themselves.

The social services board and the county department of social services recommended that local funds be used.

The board voted unanimously not to consider the abortion issue until it has more information on the funding question.