A leading Fairfax County land-use lawyer surprised members of the county's planning commission last Saturday when he told them that whatever actions they might take on a pending controversial land-use change would not really matter.

Attorney Grayson Hanes said his client, Robert Thoburn, is not going to wait for commission action on a proposal to change the comprehensive land-use plan from residential to commercial on more than 49 acres in the northeast corner of the Hunter Mill Road and Dulles Airport Access Road interchange.

"We are preparing a rezoning case on the northeast quadrant," Hanes, a member of the law firm of Hazel, Beckhorn and Hanes, told commissioners.

The process for getting land rezoned in Fairfax from residential to commercial starts with a change in the comprehensive land-use plan, according to county policy. After the land plan is changed, a rezoning application is filed. Fairfax is currently in the middle of its 1985 review of its master plan.

Thoburn's latest action may be an attempt to force a decision on the future of the Hunter Mill-Dulles road interchange out of the hands of the planning commission and into the Virginia courts. Thoburn would have the right to appeal a denial of a rezoning to the Circuit Court. Several other lawyers said a lawsuit based on a planning commission denial of a proposal would be much more difficult to win than one based on the denial of a rezoning. There are many precedents in Virginia that have generally upheld decisions by planning boards that were consistent with accepted long-range land-use plans.

"Last week I sent a letter to withdraw the application," Hanes said. "We are preparing a rezoning case."

The proposed land-use change, along with another by Thoburn for 69.7 acres on the northwest corner of the interchange, and an application by Boston Properties for commercial use of 166 acres on the southeast corner of the same interchange, have generated intense citizen opposition. The Fairfax County planning staff has recommended denial of all three applications.

Commission member John Thillmann, within whose district the property lies, denied Hanes' request to withdraw the application because Thillmann said it is part of an overall request for an amendment changing the land-use plan for land on both sides of Hunter Mill Road north of the Dulles Airport Access Road. "You say you're going to file a rezoning? Do you view this plan amendment process as a charade?" Thillmann asked.

"I don't think it is a complete charade," Hanes said.

Hanes did not say what the rezoning application would seek, and Thoburn has not revealed details of his proposed projects.

Even though Thoburn has not specifically said what he wants to build, development of the Thoburn and Boston Properties sites could produce 4.5 million square feet of office space and create a third development center, along with Tysons Corner and Reston, in western Fairfax.

The proposals have spurred citizens in the area to form the Hunter Mill Defense League, representing 39 civic associations in the Hunter Mill Road, Reston, Vienna and Oakton areas. The league has proven to be a major force in this year's plan amendment process.

The filing of applications by Thoburn has caused troubles for Boston Properties even though company officials have not said so. Boston Properties last year filed a similar application for a land-use change on the same 166 acres for a mixed-use development with a small residential community along Hunter Mill Road to buffer existing residential areas.

However, Thoburn and Boston Properties jointly hired the same transportation consultant to come up with traffic studies that resulted in dramatic plans for traffic improvements, including a new interchange along the Dulles Airport Access Road west of the present interchange at Hunter Mill.

After several nights of deferred public hearings, residents got their chance to speak out at an early Saturday morning hearing. "Our purpose is not to stop development but to support development in accordance with the adopted land-use plan, the plan by which we built our homes," John E. Mansfield, a defense league member, said. He asked commissioners to stick with the current plan "so that single-family development in this area can go forward."

Speaking for Boston Properties, attorney Ed Prichard said, "Approximately $97.5 million would go into the public treasury just from the Boston Properties' proposal."

In a recent letter to Fairfax officials, Mortimer B. Zuckerman, chairman of the board of Boston Properties, said his company's proposal would provide "continuing opportunities to attract prestigious corporations to a carefully planned and strategically located office park site of unparalled excellence in Fairfax County's growth corridor between Tysons Corner and the Dulles Airport."

Residents said traffic generated by the proposal would choke existing roads and hurt the character of their neighborhoods.