A Fairfax County School Board committee this week will consider postponing more than half the 16 school renovations in its five-year proposed construction plan by one or two years in order to preserve the county's cherished AAA bond rating.

The proposed reductions in the School Board's construction plan for fiscal 1987-91 -- which were demanded by County Executive J. Hamilton Lambert -- have produced a split on the board between supporters and opponents of any changes. Some say the suggested cuts raise the issue of equity between the county's older and newer neighborhoods.

Assistant School Superintendent Alton C. Hlavin described the reductions he proposed as "significant modifications" to the plan that the board approved Jan. 23. Laura I. McDowall, who heads the School Board's facilities committee, said such major changes should require new public hearings -- a move that could shorten time supporters need to wage a bond referendum campaign this year.

The proposed reductions would postpone renovations to four unidentified elementary schools, two intermediate schools and four high schools, accounting for more than half the number of schools to be renovated. It would trim $20 million from the proposed $25 million spending for air conditioning at older schools and would shift some spending for roof repair, science laboratories and other projects to general funds rather than bond funds.

The School Board construction plan includes seven new elementary schools, an intermediate school, 11 elementary school additions, three special-education centers and 11 elementary school gymnasium-music room additions. None would be affected by the changes.

Lambert had warned that the original construction plan approved by the board would push total county five-year bond spending $73 million over guidelines set by the Board of Supervisors. The guidelines call for the county to sell no more than $400 million in bonds over five years and aim for an $80 million annual target with an absolute ceiling of $100 million.

The county's AAA bond rating is the highest possible and allows the county to sell its bonds at the lowest interest rate.

The proposed reductions would lower total county bond spending to $412 million, for an average of $82 million annually, according to school system figures.

Although the changes would reduce the size of the five-year bond package, school system figures show that the savings would be offset by $6.1 million in additional costs because delaying projects means their price tags rise each year with inflation.

The School Board's facilities committee is to discuss the proposed changes at a meeting tomorrow; a split is emerging on the issue.

Chairman Mary E. Collier said she is satisfied that the board will be able to build all the projects it has proposed. Far from being cast in stone, the five-year construction plan "is a fluid document," she said. "It is a planning document."

But McDowall is challenging the changes, saying that the originally approved plan includes only vital projects and that the county can afford to pay for them.

"I am very disturbed by the events of the last couple of weeks," she said. "I don't believe Fairfax County is in such terrible financial shape that we cannot afford to meet the needs required by growth."

McDowall said the proposed reduction "really hits the equity issues hard" because new schools in fast-growing neighborhoods would stay on schedule but renovations to schools in established areas would be delayed.

Former School Board member Toni Carney said she is disturbed that the Board of Supervisors, not the School Board, appears in this case to be dictating the county's education agenda.

"You are the public's voice to the Board of Supervisors -- not the reverse," Carney said in a speech last week to the school panel she served on as Springfield district representative for six years. "The more accommodating you become, the more compromised you become."