Aeronautical Chart in Wartime and Postwar

Posted by Admin on

Wartime
World War II compressed a quarter-century of peacetime aeronautical chart development into a few years. The need for all types of charts was urgent and insatiable. The term “aeronautical chart” became firmly established during this time. Previously, charts were referred to as air maps, aeronautical maps, flight maps, or aeronautical charts. Most charts were variations of those in existence prior to 1939, which saved precious time during the war. Charts rolled off the presses by the millions. At its peak, the production of charts in the St. Louis plant reportedly reached 10 tons a day.

New radio navigation aids were developed for en-route position finding during the war. The Coast and Geodetic Survey started developing a series of radio direction-finding charts in 1939 to cover the United States. The long range navigation (loran) system was established on the East Coast in 1941. New charts were developed to accommodate this new navigation system and a new series of world aeronautical chart (WAC) scale maps for the Western Hemisphere were developed and subsequently completed for the rest of the world in 1943. Additional series for world planning and world long-range charts were initiated. In 1942, the first of a new series of instrument approach and landing charts was distributed by the geodetic survey.

The aeronautical chart service used the Lambert conformal projection; the Navy’s Hydrographic Office employed the Mercator projection. For planning and operating within a global system, new projections were introduced and old systems adapted. The Lambert conformal was preferred for its accuracy in air navigation for most parts of the world; however, for navigation in polar regions, charts using the transverse Mercator or polar stereographic projections were selected.

Postwar
By the end of the war, responsibility for revising and distributing world aeronautical charts covering the continental United States was turned over from the military to the Coast and Geodetic Survey. International conferences began shortly after the war and established criteria and requirements to serve the needs of aircraft engaged in international flights.

From the middle to late 1940s, the U.S. Air Force published Instrument Let Down publications. These procedures were bound volumes consisting of four charts to each page produced by the Coast and Geodetic Survey. A new series of radio facility charts was introduced by the survey in 1947, superseded two years later by a series of 59 standard radio-facility charts covering the entire United States.

Jeppesen introduced the Standard Instrument Approach Procedures in 1947. Prior to this time, instrument approach procedures were designed by individual operators, for their own use, then approved by the Civil Aeronautics Authority (CAA), which was the predecessor to the Federal Aviation Administration (FAA). Jeppesen and the CAA developed a program where the CAA would provide standard approach procedures and authorize operators to use those procedures. The first instrument landing system (ILS) approach chart was developed in 1948, followed a year later with the first very-high-frequency omnidirectional radio range (VOR) approach chart. Supplemental flight information documents were introduced in the early 1950s to keep pace with an increasing amount of navigational information.

Dunlap and Associates was given a contract by the U.S. Office of Naval Research in 1951 to study aeronautical charts and other graphical aids to navigation. Dunlap reported “two trends in the development of aeronautical charts. First, charts have become more complex because there has been a tendency to add new information to already existing charts. Second, there has been developed a wide variety of aeronautical charts so that the pilot must go to many sources to gather the information he or she needs. Both trends have been due to the increasing complexity of flight.” Also during this period the Airman’s Guide, Directory of Airports, and Flight Information Manual replaced Airway Bulletins.

Previous
« Prev Post