The Fairfax County Board of Supervisors chairman and county executive said yesterday they no longer object to the School Board's five-year proposed construction plan because they are satisfied it will not endanger the county's AAA bond rating.

County Executive J. Hamilton Lambert had warned that the $196 million plan adopted by the School Board in January was so expensive it would push the county's total bond needs $73 million over the five-year guideline set by the Board of Supervisors, which must approve any bond issues.

That prompted Assistant Superintendent Alton Hlavin to draft a proposal to postpone by one or two years 10 of the 16 school renovations included in the plan. Some county residents protested, and School Board members rejected that alternative as too drastic.

The statements of satisfaction by Lambert and Board Chairman John F. Herrity appear to end a week of controversy over the county's ability to pay for the needs that the School Board said are crucial to respond to housing growth and to provide new programs.

Lambert said yesterday his concern had been with the schools' yearly cash needs. He said he is now satisfied that the spending can be spaced out beyond the five-year period by paying for some projects after completion to stay within the supervisors' guidelines. The AAA bond rating is the highest possible and enables the county to sell bonds at the lowest possible interest rate.

Superintendent Robert R. Spillane gave the School Board two proposed bond package alternatives Tuesday night -- one for a two-year program totaling $118 million, another for a three-year program totaling $137 million. "We'll certainly be able to fund that," Lambert said yesterday.

The bond package agreed on would go to the voters in November as the first installment in paying for the massive building plan, which would put up eight schools, three special education centers and additions to 11 elementary schools, and undertake renovations at 16 schools over fiscal 1987-91.

Herrity, who had objected to the size of the construction plan, said the superintendent's bond proposal answered his criticism by including only $5 million for air conditioning, instead of the $25 million originally proposed, and shifting some repairs to its general-fund budget.

Spillane suggested that Lambert's memo warning the plan was too big should never have been sent, and some county civic activists said it appeared the county executive was trying to dictate action to the School Board. But others, including Herrity and School Board Chairman Mary E. Collier, said the proposal to postpone the renovations was an overreaction and was never seriously considered.

"It was a communications difficulty on both sides," Lambert said. "I'm not interested in fighting with anybody."

But two supervisors -- James M. Scott and Audrey Moore, both members of the board's Democratic minority -- said the issue raised an important question for the county: Can it afford to pay for all the needs its fast growth has brought?

"Until this all surfaced, I was at least able to say we could build the schools we needed and build the roads we needed," said Scott. "Now at least that issue has got to be discussed some more."