The Fairfax County School Board yesterday rejected a fact-finder's recommendation that it offer a head coaching job to a high school coach who was fired last year for eavesdropping on an opposing football team.

"I fully expect that we'll challenge their decision in court," said Rick Willis, executive director of the Fairfax Education Association, which represents former Langley High School coach Mike Weaver.

Weaver said he had no comment about the decision except, "I want to coach football."

The union says the School Board missed a 30-day deadline to take action on the fact-finder's report, which was signed Oct. 7. The School Board says the 30-day period began Nov. 13, when the school system staff sent the report to board members at their homes. The board held an unusual Saturday session to beat that deadline.

Weaver was fired Oct. 8, 1986, as Langley head coach after an investigation disclosed that his staff eavesdropped on radio conversations of coaches from Madison High School during a game between the two football teams the previous week. Langley lost the game 14-7.

Weaver filed a grievance, contending that the basis cited for firing him -- a Virginia High School League rule that coaches are expected to maintain ethical standards -- did not apply to his case, sources said.

After Weaver lost several appeals within the school system, the case was turned over to a fact-finding panel, whose report said the school system overreacted, Willis said. The report said that Weaver should be offered a head coaching job, according to Willis.