In Hawaiian Airlines v. Norris, 512 U.S. 246, 258, 114 S. Ct. 2239, 129 L. Ed. 2d 203 (1994), the United States Supreme Court most recently analyzed the scope of federal preemption under the RLA. There an aircraft mechanic, after first invoking the grievance procedure under a CBA, filed suit in state court claiming that his discharge was retaliatory and violated the Federal Aviation Act of 1958 and Hawaii's Whistleblower Protection Act. Hawaiian Airlines, 512 U.S. at 250. The Supreme Court found that the mechanic's wrongful discharge claims were not preempted because they involved substantive rights provided by state and federal law, independent of the CBA. Hawaiian Airlines, 512 U.S. at 256-57. The Court found that the RLA's preemption of "minor" disputes extends only to disputes that invoke contract-based rights and are "grounded in the CBA." Hawaiian Airlines, 512 U.S. at 254-56. "'The distinguishing feature of a minor dispute is that the dispute may be conclusively resolved by interpreting the existing CBA'." Hawaiian Airlines, 512 U.S. at 256. But where the resolution of a state law claim depends upon "purely factual questions" about an employee's conduct or an employer's conduct and motives, and does not require a court to interpret any term of a CBA, then such claim is not preempted. Hawaiian Airlines, 512 U.S. at 261. When the meaning of contract terms is not at issue, the fact that a CBA will be consulted in the course of state law litigation, or that a remedy may potentially be available under a CBA, does not deprive an employee of independent remedies available under state law. Hawaiian Airlines, 512 U.S. at 261 n.8.