Precision Instrument Runway Approach Zone. The height limitation slopes 50 feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of 10,000 feet along the extended runway center line; then the limitation slopes upward 40 feet horizontally for each foot vertically to an additional horizontal distance of 40,000 feet along the extended runway center line.

Runway Larger Than Utility With a Visibility Minimum Greater Than Three-Fourths Mile Nonprecision Instrument Approach Zone. The height limitation slopes 34 feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of 10,000 feet along the extended runway center line.

Utility Runway Visual Approach Zone. Slopes 20 feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of 5,000 feet along the extended runway center line.

Runway Larger Than Utility With A Visibility Minimum As Low As Three-Fourths Mile Nonprecision Instrument Approach Zone. Slopes 34 feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of 10,000 feet along the extended runway center line.

Transitional Zones. The height limitation slopes seven feet outward for each foot upward beginning at the sides of and at the same elevation as the primary surface and the approach surface and extending to a height of 150 feet above the airport elevation. In addition to the foregoing, there are established height limits sloping seven feet outward for each foot upward beginning at the sides of and at the same elevation as the approach surface and extending to where they intersect the conical surface. Where the precision instrument runway approach projects beyond the conical zone, there are established height limits sloping seven feet outward for each foot upward beginning at the sides of and at the same elevation as the approach surface and extending a horizontal distance of 5,000 feet measured at 90º angles to the extended runway center line.

Horizontal Zone. The height limitation is established at 150 feet above the airport elevation.

Conical Zone. The height limitation slopes 20 feet outward for each foot upward beginning at the periphery of the horizontal zone and to 150 feet above the airport elevation and extending to a height of 350 feet above the airport elevation.

Accepted height limitations. Nothing in this article shall be construed as prohibiting the construction or maintenance of any structure or growth of any tree to a height up to 50 feet above the surface of the land.

Regulations not retroactive. The regulations prescribed by this article should not be construed to require the removal, lowering or other change or alteration of any structure or tree not conforming to the regulations as of the effective date of this article or otherwise interfere with the continuance of a nonconforming use. Nothing contained herein shall require any change in the construction, alteration or intended use of any structure, the construction or alteration of which was begun prior to the effective date of this article and is diligently prosecuted.

Marking and lighting. Notwithstanding the preceding provision of this section, the owner of any existing nonconforming structure or tree is hereby required to permit the installation, operation and maintenance thereon of such markers and lights as shall be deemed necessary by the Township Supervisors to indicate to the operators of aircraft in the vicinity of the airport the presence of such airport obstruction. Such markers and lights shall be installed, operated and maintained at the expense of Johnstown Cambria County Airport Authority or any successor organization or corporation.

Future uses.

Existing uses. No zoning approval shall be granted that would allow the establishment or creation of an obstruction or permit a nonconforming use, structure or tree to become a greater hazard to air navigation than it was on the effective date of this article or any amendments thereto or than it is when the application for a zoning approval is made. Except as indicated, all applications for such zoning approval shall be granted.

Variances. Any person desiring to erect or increase the height of any structure or permit the growth of any tree or use property not in accordance with the regulations prescribed by this article may apply to the Zoning Hearing Board for a variance from such regulations. Such variances shall be heard in accordance with the standards and procedures set forth in Article XVI of this chapter and may be allowed where it is duly found that a literal application or enforcement of the regulations will result in unnecessary hardship and that the relief granted will not be contrary to the public interest, will not create a hazard to air navigation, will do substantial justice and will be in accordance with the spirit of this article. Additionally, an application for variance from the requirements of this article may be referred by the Zoning Hearing Board to the Johnstown Cambria County Airport Authority or the Johnstown Cambria County Airport Manager for advice as to the aeronautical affects of the variance.

Obstruction, marking and lighting. When such action is deemed advisable to effectuate the purpose of this article and to be reasonable in the circumstances, a granted zoning approval or variance may be conditioned to require the owner of the structure or tree in question to install, operate and maintain, at the owner's expense, such markings and lights as may be necessary. If deemed proper by the Zoning Hearing Board, this condition may be modified to require the owner to permit the Johnstown Cambria County Airport Authority, at its own expense, to install, operate and maintain the necessary markings and lights.