(1) Introduction. In order to provide uniform criteria for determining obstructions to air navigation, this standard has been adopted by the Washington state aeronautics commission.

(2) Directive. In accordance with the procedure for establishing technical aeronautical standards specified in state obstruction marking and lighting law, "Criteria for determining obstructions to air navigation" set forth below is established as a state standard. This standard is the official Washington state aeronautics commission guide for determining obstructions to air navigation and supersedes all existing obstruction criteria which do not conform to its requirements.

(3) Specific instructions. Procedure for determining obstructions.

(a) Any structure or obstacle which obstructs the air space above ground or water level, when determined by the commission after a hearing to be a hazard or potential hazard to the safe flight of aircraft, shall be plainly marked, illuminated, painted, lighted or designated in a manner to be approved in accordance with the general rules and regulations of the commission so that the same will be clearly visible to airmen. In determining which structures or obstacles constitute or may become a hazard to air flight, the commission shall take into account only those obstacles located at river, lake and canyon crossings and in other low altitude flight paths usually traveled by aircraft. (Same as RCW 14.04.340.)

(b) The director shall have the authority to require owners, operators, lessees or others having the control or management of structures or obstacles over one hundred fifty feet above ground or water level and which are or may become a hazard to air flight to report the location of such existing or proposed structures or obstacles to the commission. For that purpose the director may issue subpoenas and subpoenas duces tecum returnable within twenty days to the commission. In the event a person refuses to obey the director's subpoena, the commission may certify to the superior court all facts of any such refusal. The court shall summarily hear evidence on such refusal, and, if the evidence warrants, punish such person refusing in the same manner and to the same extent as for contempt committed before the court. (Same as RCW 14.04.350.)

(c) Objects which are located or will be located with respect to other objects of a permanent character such that there results no material increase in the aeronautical hazard will not be considered obstructions.