Wash. Rev. Code § 47.68.280
The department or any officer or employee of the department designated by it has the power to hold investigations, inquiries, and hearings concerning matters covered by this chapter including accidents in aeronautics within this state. Hearings shall be open to the public and, except as hereinafter provided, shall be held upon such call or notice as the department deems advisable. The department and every officer or employee of the department designated by it to hold any inquiry, investigation, or hearing has the power to administer oaths and affirmations, certify to all official acts, issue subpoenas, and order the attendance of witnesses and the production of papers, books and documents. In case of the failure of a person to comply with a subpoena or order issued under the authority of this section, the department or its authorized representatives may invoke the aid of a competent court of general jurisdiction. The court may thereupon order the person to comply with the requirements of the subpoena or order or to give evidence touching the matter in question. Failure to obey the order of the court may be punished by the court as a contempt thereof.
RCW 47.68.280