Airway Marking - Identification of Cities and Towns
In 1922 experiment were conducted by the Army Air Service in painting the names of cities and towns on the roofs of prominent buildings along a section of its Model Airway between Dayton, Ohio and Washington, D.C. The value of this experiment as an aid to aerial navigation was immediately apparent and to a great extent eliminated forced landings from pilots becoming lost. Navigation of the air, even under favorable conditions, is difficult for the novice, but when attended by fog, low clouds, rain or snow, it becomes exceedingly difficult and often necessitates a descent by a pilot to establish his location if possible. In the past it has been the practice of some to dive toward a railway station hoping to read the name with a fleeting glance -- a very dangerous proceeding both to the airman and those in the vicinity of the station. Others would attempt landings in unsafe fields to learn of their location. Crack-ups were a frequent result.
Size of Signs
When the names of cities are painted in 6- to 12- ft. letters on the roofs of prominent buildings -- preferably adjacent to the railway -- a great contribution will have been made toward the safety of flying. A campaign for the general support of this practice by cities along well-traveled air routes has had a generous measure of support throughout the United States by civic, patriotic and industrial organizations as well as some of the larger corporations having branches and agencies at desirable locations (such as that seen in photograph below).
City identification as shown above is of great value to aerial navigators
(Urbanna, Virginia)
It should be borne in mind that letters less than 6 ft. in height cannot be read at high altitudes. Color contrast is likewise not important -- white letters on a dark background being preferable. While a tin roof furnishes the best painting surface, tar-gravel or composition roofs may be used by placing strips of white canvas or white letters cut from suitable lumber. Care should be taken, however, to determine whether such procedures may invalidate the guarantee of the roof contractor.A description of the method employed on the Palmer Building in Atlanta, Georgia, which is unique in its originality and value as an advertising medium, is given below for the benefit of others who may be confronted with similar conditions:
The word "PALMER" is in letters approximately 10 ft. in height. The arrow pointing to the landing field is approximately 25 ft. in length. The letters in the word "ATLANTA" are about 40 ft. in height. All of the sign is of wood raised on short legs approximately 8 in. off the roof so that proper water drainage underneath is accomplished. All wood is painted white. The roof itself is a solid concrete slab covered with roofing paper, tar and gravel.
Palmer Building, AtlantaThe gravel was of such a light color that is did not form originally a background dark enough properly to display the white letters. This mistake was corrected by raking up the gravel immediately around the letters , saturating it with a black creosote substance and then re-raking it into a position which gave the black background as seen from the photograph.
Permission to Mark
The local aero organization, Chamber of Commerce, or other civic association, should obtain permission to place the marker upon the roof of some large prominent building, adjacent to the railroad right-of-way, and preferably on the outskirts of the city where visibility is least affected by factory smoke.Instructions
The roof selected should be of tile, shingle, tin or other metal, or of slate composition. Gravel and pitch roofs do not furnish a good painting surface but may be used for white wooden letters, of the proper dimension, elevated slightly above the roof to facilitate drainage underneath.A simple block letter in white, with a dull black background, should be used. If the roof has a slope of over 30 degrees, the sign should be painted on both sides.
The width of the letter should equal two-thirds of the height (this pertains to such letters as M or W -- other letters in proportion). A spacing of one-fourth the height should be used between letters. Letters from 6 to 12 ft. in height are recommended, depending on space available.
Whom to Notify
After the name of a city has been placed on one or more roofs as suggested, the Aeronautics Branch, Department of Commerce, Washington, D.C., should be notified and an aerial photograph of same forwarded, if possible. This information is recorded and such cities are marked on Air Navigation Maps with distinguishing characters.
A discussion from: Airports and Airways: Cost, Operation and Maintenance.
by Donald Duke and published by Ronald Press, NY, 1927.
