A superior court judge has sided with the Martha’s Vineyard Airport Commission in its ongoing dispute with the Dukes County Commission over the legal independence of the airport.

In a written opinion, the Hon. Richard Chin, an associate justice of the superior court, granted the airport commission a preliminary injunction that allows it to exclude the county manager as an ex officio nonvoting member of the airport commission. He also ordered that the county treasurer may not refuse to pay the airport legal bills and does not have the right to see privileged communications between the airport commission and its attorneys.

Judge Chin denied a request from the airport to dismiss a series of counterclaims by the county, but in all other matters the 11-page decision sides squarely with the airport commission on questions of control and authority over airport affairs.

A preliminary injunction is not a final ruling, and the case will now proceed to trial, but injunctions are granted to prevent the likely winner of a lawsuit from suffering irreparable harm while waiting for the final outcome.

The county commission is the appointing authority for the airport commission. The two commissions have sparred on and off for years over who ultimately controls the airport, which is owned by the county but financially independent from it. The county operates under a state charter while the airport operates under a different state act, enacted after the charter.

In 2005 a superior court case brought by former airport manager William Weibrecht confirmed the airport’s authority to set salaries and contracts for its employees.

In the latest lawsuit, filed in May, the airport seeks expanded recognition of its autonomy from the county. The complaint stems in part from a decision by the county commission earlier in the year to name the county manager to the airport commission as an ex-officio member. The airport commission has refused to allow county manager Martina Thornton to participate at meetings. There has also been disagreement and tension between the two commissions over how the county treasurer has been handling legal bills.

At a hearing in the Edgartown courthouse last month, Judge Chin heard arguments from attorneys for both sides on the motions by the airport for injunctive relief and dismissal of the counterclaims. Attorneys for the county argued that because the county appoints the airport commission, it has ultimate control. But attorneys for the airport said allowing the county to make organizational changes could jeopardize state and federal grant assurances which provide millions of dollars in funding for airport operations.

In the ruling dated August 12, Judge Chin agreed with the airport on the matter of grant assurances and said adding the county manager to the airport board as an ex-officio member could be construed as a reorganization of the board. The county charter provides for the appointment, raising the broader question of whether the county charter trumps the airport act.

Referring back to the 2005 Weibrecht case, Judge Chin said it does not.

“The county commission argues that the Weibrecht decision is narrow in scope, addressing only the power to set salaries for the airport manager and assistant manager, and is consequently irrelevant to the issues before the court in this case. The court disagrees,” he wrote. “The court agrees . . . that the charter, a broad enabling statute, does not supersede the narrowly tailored airport act even thought it was enacted afterwards.”