WASHINGTON (AP) _ The Supreme Court today agreed to use an airline pilots' lawsuit to clarify the procedure for non-union workers to challenge fees they are required to pay to a union under an agency-shop agreement.

The court said it will hear the Air Line Pilots Association's argument that non-union pilots must go through arbitration before taking their challenge to court.

The pilots' union contract with Delta Air Lines includes an agency shop agreement, which requires non-members to pay the union a service charge to help cover contract negotiation expenses.

Non-union members who file an objection cannot be required to pay other union expenses, and they were to be given a credit or rebate for those costs. The contract provided an arbitration procedure for those who wished to challenge the union's calculation of the size of the rebate.

A group of pilots requested arbitration of the 1992 rebate calculation, and an arbitrator ordered some changes in the rebate amount.

Some pilots previously had asked a federal judge in Washington D.C. to stop the arbitration and to resolve the dispute over union fees. The judge refused and ruled in August 1995 that non-union members who want to challenge such fees must first go through arbitration before going to court.

The U.S. Circuit Court of Appeals for the District of Columbia reversed. Non-union members need not go through arbitration because they never agreed to do so, the court said.

In the appeal acted on today, lawyers for the pilots' union said other federal appeals courts have ruled that non-union members must go through arbitration first.

Attorneys for the non-union pilots said the lower court correctly ruled that they are not bound by the arbitration language in the union contract.

The case is Air Line Pilots Association vs. Miller, 97-428.