Fairfax County is apparently delaying decisions on pending rezonings for tall buildings in the Tysons Corner area until the Board of Supervisors acts on a controversial new height study of existing and potential building elevations in the Tysons area.

In a surprise move, the board recently quietly agreed to go along with a request by Centreville Supervisor Martha Pennino to defer action on a pending proposal by the Hadid Investment Group to develop a 12-acre site along the Leesburg Pike until action is taken on the height study.

Both Pennino and Dranesville Supervisor Nancy Falck said the height study is long overdue, but Fairfax has approved many major high-rise projects in the Tysons area without the benefit of the study, which Pennino first requested more than four years ago.

Falck this week said she will ask the Board of Supervisors Monday to appoint a special citizens task force to review the height study and report back to the board by next fall.

The recent move to delay action on the Hadid proposal has generated charges that decision-makers are trying to change the rules in the middle of the game. Action on other pending applications is expected to be delayed, but most other proposals are not as extensive as Hadid's.

The height study was submitted by the county planning staff as an attempt to amend the county land-use plan during the current annual review process. Residents from three magisterial districts that come together in the Tysons Corner area -- Dranesville, Centreville and Providence -- will be asked to serve on the task force. Falck said she had talked over her plan with Pennino and Providence Supervisor James Scott.

"It is an important study. It should not be treated lightly," Falck said. "The proposals in the plan are too difficult to deal with as a plan amendment," she said. There are more than 290 plan amendments that must be dealt with by other citizen task forces and the county planning commission and supervisors before midsummer.

"We ought to get it out of a time frame that is cluttered so that we can be very clear about this matter," Falck said.

Pennino said she supports the task force. "The citizens are the ones who are going to have to live with it," she said.

Ironically, the latest proposal by the Hadid Group for the site now occupied by the Koons Pontiac dealership on the south side of Route 7 west of Tysons Corner Shopping Center and east of the Dulles Toll Road appears to be in compliance with the recommendations included in the new height study.

The study calls for the future redevelopment of car dealerships along Route 7 and says the Koons site has great redevelopment potential. "The existing Koons Pontiac site has potential as a district focal point," the study says. In many parts of the study, focal points are considered tall buildings. In addition, the study says height on the Koons site could be justified up to 150 feet if the development provided retail use on the main level and pedestrian access to other nearby structures.

Several developers who were ready to file plans for height increases or increased density in the Tysons area said this week they are considering delaying filing applications.

Attorney Martin Walsh, representing the Rosslyn-based Hadid, said his client is ready to put aside plans to build anything that would require board approval and instead build what is permitted under existing zoning. That probably would mean four seven- or eight-story buildings near the 23-story Sheraton hotel now under construction nearby on the same side of Route 7.

Pennino pushed for the height study when the Sheraton application was first filed four years ago.

"Citizens have to realize that height doesn't necessarily mean increased density," Pennino explained. She said she is not endorsing the Hadid proposal, adding that she hoped the developer would wait until the height study was evaluated before building anything.

Walsh said his client may have too much invested to continue waiting. Mohammad (Michael) Hadid, head of the development group, had reportedly wanted to build a landmark building on the site to help further establish himself as a Northern Virginia builder. A native of Arlington, Hadid originally wanted to put a 30-story hotel on the Koons site but later revised the plan to a 22-story office tower.

In early February, Walsh told a local citizens group that the plans had been changed again as a result of community input. Walsh said two 12- or 13-story office buildings connected by a atrium would be built. "We are in total compliance with the new height study," Walsh told the McLean Citizens Association's planning and zoning committee just a few days after the height study was released.

Within a week Walsh said he was told that action had been deferred indefinitely on the Hadid plan. Walsh said his client is considering this week proceeding with construction of a low-rise building on the front portion of the site in a design that might permit construction of tall buildings in the future depending upon the outcome of the height study proposals.

Some civil association leaders were surprised by the board's action. Some said they worried about the implications of being able to delay a decision on a project that has been in the works for more than six months because of a new study that has not been adopted as policy. Several lawyers agreed but not one would talk for the record.

"That height study has not been adopted. The board should go ahead and deal with the Hadid application without regard to the height study," said Lilla Richards, a long-time activist in the Tysons-McLean area.

"They acted on Tysons II without a height study. They acted on Tycon Towers without a height study," she said this week. In fact, a preliminary draft of the height study was in the hands of the board of supervisors immediately before the Tysons II vote.

Tysons II includes a series of high rise office buildings, a regional shopping center and a 22-story hotel. Tycon Towers is a three building complex under construction on Route 7 near the beltway, east of the Tysons Corner shopping center. Its buildings are 17 stories tall.