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Real Pilots Fly Adcock Ranges

A look at the navigation systems that preceded today's technology.

[Courtesy of Peter Garrison]
Gemini Sparkle

Key Takeaways:

  • Early air navigation evolved from visual landmarks and beacon lights to the Low-Frequency Four-Course Range (LFR) system, which enabled instrument flying.
  • The LFR, prominent from the late 1920s, used ground antennas to broadcast Morse code signals, creating four audible "beams" pilots followed by maintaining a continuous tone in their headsets.
  • This system was succeeded by hybrid technologies like the Visual Aural Range (VAR) in the 1940s, a precursor to today's VOR (Very High Frequency Omni-directional Range).
  • The article highlights the vast advancements in air navigation, contrasting the challenging and often perilous methods of the past with the safety and convenience offered by modern GPS.
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A friend bought me an old aeronautical chart he found in a map store. Dated August 16, 1953, it covers roughly the same area as the current Los Angeles VFR [visual flight rules] terminal area chart. In the lower margin are the words: “PRICE 25 CENTS.” You got more square miles for your money then than you do today, even taking inflation into account.

The scene depicted on the chart is at once familiar and strange. Many small airports have vanished; runway diagrams of some larger ones have changed. There are only three VORs [very high frequency omni-directional range]: Long Beach, Ontario, and Palmdale. The airways are 10 statute miles wide—the FAA did not go nautical until the mid-1960s—and they are defined by what look like localizers. They aren’t localizers, however; they’re the beams of four-course ranges.

Peter Garrison

Peter Garrison taught himself to use a slide rule and tin snips, built an airplane in his backyard, and flew it to Japan. He began contributing to FLYING in 1968, and he continues to share his columns, ""Technicalities"" and ""Aftermath,"" with FLYING readers.

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