The pros and cons of converting Fairfax County into a city were debated briefly this week by the Board of Supervisors. But the discussion stirred up more questions than answers, and the issue finally was referred to a special subcommittee for further study.

"The time has come for the county to consider moving to city status," argued board Vice Chairman Martha V. Pennino (D-centreville), who contended that city status would give the county's more than 600,000 residents greater clout with the state and federal governments.

Pennino, noting that Fairfax would be the 18th largest city in the nation, said governments "understand cities" but have trouble identifying with the problems of urban counties. In the eyes of the General Assembly, she complained, "We are neither fish nor fowl."

And, Pennino warned, unless the county becomes a city, it could be the target of annexation moves by neighboring Falls Church, where the City Council already is discussing annexation as a way to boost its sagging school population.

But Supervisor Audrey Moore (D-Annandale) argued against the plan, citing a study by a special committee that concluded that as a county, Fairfax has the "best of both worlds."

As a city, Moore said after the meeting, Fairfax would have the right to operate its own road system and would not have to seek voter approval on bond issues to pay for the roads. But maintaining its own roads could cost county taxpayers "a lot of money," she said.

Moore said the push for city status by Pennino and others is simply a last-ditch way to find the funds to build the Springfield Bypass, a sort of minibeltway linkd-up to major commuter routes.The county, Moore said, has been trying to get the bypass built for years, but has had its tax proposals for funding the ,125 million project rebuffed by the General Assembly.

Moore theorized that the real reason behind last weekend's Northern Virginia tour for General Assembly members was to lay the groundwork for presenting yet another bypass funding plan to lawmakers.

"It's not a good idea to brag to others about how big and rich you are, unless you're trying to impress the legislators that you're a good risk," said Moore. "But I talked to some of the delegates about whether they were willing to do this for us, and they gave me a kind of green look."

Despite the opposition to the city proposal, Pennino said she expects that sooner or later the county will recognize the benefits of becoming a city.

"I don't think it will make one bit of difference to the citizens," she said, "but it will be beneficial to the governing body and the county staff."