Obstruction Marking of ILS Glide Slope Antenna Towers

6750.26 · FAA

Public domain · FAAOrders & Notices

Overview

The Obstruction Marking of ILS Glide Slope Antenna Towers (6750.26) is a public-domain FAA order, republished here as a free chaptered HTML edition with a linked table of contents and the official PDF.

Publisher: FAA
Document: 6750.26
Pages: 1

Key points

This order provides guidance on the obstruction marking requirements for ILS glide slope antenna towers.
ILS glide slope antenna towers are erected up to a maximum height of sixty feet and may be modified in the field.
The Air Traffic Service has approved a deviation from standard obstruction marking requirements for these towers.
Obstruction marking must include a minimum of three alternating bands of aviation orange and white, with the top band being aviation orange.
At the first repainting of the towers, the obstruction marking must be revised to conform with AC 70/7460-1D standards.

Frequently asked questions

What is the purpose of this order?

The purpose of this order is to provide guidance on the obstruction marking requirements for ILS glide slope antenna towers.

What are the height specifications for ILS glide slope antenna towers?

ILS glide slope antenna towers are generally erected up to a maximum height of sixty feet.

What are the marking requirements for these towers?

The marking requirements include a minimum of three bands of aviation orange and white, with the top band being aviation orange.

What happens at the first repainting of the towers?

At the first repainting of the towers, the obstruction marking must be revised to conform with AC 70/7460-1D standards.

Can the widths of the marking bands vary?

Yes, the widths of the alternating bands may not be equal or one-seventh of the tower height, but they must be no wider than fifteen feet nor less than one and one-half feet.

Document

DEPARTMENT OF TRANSPORTATION

ORDER

FEDERAL AVIATION ADMINISTRATION 6 750. 26 3/2l/75 SUBJ: OBSTRUCTION MA~KING OF ILS GLIDE SLOPE ANTENNA TOWERS 1. PURPOSE. This order provides guidance on the obstruction marking requirements for ILS glide slope antenna towers.

2. DISTRIBUTION. This order is distributed to branch level in Airway Facilities, Air Traffic and Flight Standards Services within Washington and regional headquarters; to branch level at the FAA Depot and Airway Engineering Support Division at the Aeronautical Center; and to division level at NAFEC.

3. BACKGROUND. ILS glide slope antenna towers are generally procured in five, ten, and/or twenty-foot sections with obstruction painting factory applied. These sections are erected in the field up to a maximum height of sixty feet. Sometimes, the tower sections are modified in the field to shorten the overall tower height somewhat to meet technical requirements needed to achieve the precise glide slope angle required. As a result, the widths of the alternating bands of orange and white may be neither equal nor one-seventh of the tower height, and the top and/or bottom band may not be orange - as required by Advisory Circular AC 70/7460-lD, Obstruction Marking and Lighting.

4. OBSTRUCTION MARKING REQUIREMENT. The Air Traffic Service has approved a deviation from AC 70/7460-~to enable a more practical obstruction marking requirement for ILS glide slope antenna towers procured in sections of different heights and erected (and, sometimes, modified) in the field in various combinations, as follows: a. ILS glide slope antenna towers shall be obstruction painted in alternating bands of aviation orange and white.

b. There shall be a minimum of three bands with the top band aviation orange.

c. The bands shall be no wider than fifteen feet nor less than one and one-half feet.

,:---\d. At the first repainting of the towers, the obstruction marking ~~~be revised to conform with the AC 70/7460-W standards.

t2ARREN C. SHARP