(1) The Washington state aeronautics commission has the statutory responsibility of promoting safety in aeronautics and enforcing safety rules, regulations and standards. In the light of this responsibility, the Washington state aeronautics commission is vitally concerned with any object which may be a hazard to the safe operation of aircraft and the enforcement of state obstruction and marking law. Consequently, it has a primary responsibility in the determination of whether an existing or proposed object is, or will become, such a hazard.

(2) In order to provide uniform criteria to determine whether an object is, or will be, an obstruction to air navigation, the Washington state aeronautics commission has issued state standards for determining obstructions to air navigation. Natural or manmade objects or portions thereof, both temporary and permanent, which have been determined, through the application of these standards, to be obstructions and all manmade objects, or portions thereof, greater than 150 feet in over-all height above ground, or water if so situated, should be marked and/or lighted in accordance with the applicable standards hereinafter described, unless aeronautical study indicates that the absence of such marking and/or lighting will not impair safety in air navigation. Existing nonstandard obstruction marking and lighting installations should be replaced or modified so as to conform with these standards as soon as practicable.

(3) The standards for marking and lighting obstructions prescribed in this publication are designed to provide the most effective means of indicating the presence of obstructions to pilots. In many instances the obstruction may be so located in reference to other objects or the contour of the ground, that the specific standard need be applied to its upper part only. Similarly, the obstruction may be so removed from the general flow of air traffic or may be so conspicuous by its shape, size or color that obstruction marking would serve no useful purpose and would be unnecessary. Furthermore, the obstruction may present such a hazard that lighting should be provided similar to that for an obstruction of a greater height. Portions of obstructions that are shielded by surrounding objects need not be marked or lighted, but the surrounding objects should be marked and lighted.

(4) Because of the many influencing elements, the Washington state aeronautics commission may modify the obstruction marking and lighting standards hereinafter described when aeronautical study has indicated that a change or modification is necessary to provide adequate protection for aeronautics.