Five city of Atlanta officials on Monday prevailed in a case brought by a businessman who contends that the city rigged a lucrative airport advertising contract so it would be awarded to a political insider.

In a 20-page ruling, the 11th U.S. Circuit Court of Appeals ruled in favor of the city officials and against Corey Airport Services, which is owned by self-made millionaire Billy Corey. The legal dispute began in 2002 when the city awarded the contract to Clear Channel Airports of Georgia and its minority partner, Barbara Fouch, a close friend of the late Mayor Maynard Jackson.

The court, deciding a pre-trial appeal, did not rule on the merits of the case. Rather, it said the officials could not be held liable as individuals because, at the time, there was no law against what they did. Corey's claims against the city, which are still pending in U.S. District Court in Atlanta, were not before the 11th Circuit in this appeal.

Corey, 77, became a one-man crusade against City Hall after he lost out on the contract. He accused city officials of rampant cronyism and publicized his anti-corruption hotline on billboards.

Corey sued the city and airport general manager Ben DeCosta; concession manager Kyle Martin; Hubert Owens of the office of contract compliance; Adam Smith, chief procurement officer; and Carolyn Chavis, the city's aviation contract administrator.

The city has long said that Corey's claims are meritless and that it properly awarded the contract to Clear Channel. The advertising concession at Hartsfield-Jackson International Airport has produced $12 million to $20 million a year in gross revenue, according to court filings.

On Monday, the 11th Circuit said the city officials were shielded by qualified immunity. Under this legal principle, a government official may not be held liable if there was no clearly established law that said their conduct violated a constitutional right.

During a hearing in August, Corey's lawyer, Mike Bowers, said that the bidding process for the advertising contract was "so biased and slanted toward the incumbent Clear Channel that Corey advertising had little if any opportunity to meaningfully participate."

But the 11th Circuit said that, "whether or not this is true," there was no clearly established law at the time the contract was awarded that said such conduct was illegal. For that reason, the court said, Corey's equal protection and conspiracy claims against the five officials must be dismissed.

On Monday, Bowers said he was disappointed with the ruling. "But the bulk of Corey's claims are still in place," he said.

Acting city attorney Roger Bhandari said the city hopes to get the remaining claims dismissed as well. "From the very beginning of the case, the city has steadfastly maintained that its officials acted fairly and maintained the integrity of the bidding process," he said.