By Stars, Beacons, and Satellites | Flight Today | Air & Space Magazine
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By Stars, Beacons, and Satellites

The lost art-and intimidating science-of aerial navigation.

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One day this will be an airborne life. But by then men will have forgotten how to fly; they will be passengers on machines whose conductors are carefully promoted to a familiarity with labeled buttons, and in whose minds the knowledge of the sky and the wind and the way of the weather will be as extraneous as passing fiction.

—Beryl Markham, West With the Night

To be lost is unpleasant; to be lost at sea or in the sky is particularly so, because the very insubstantiality of the environment infuses it with latent menace. Having been lost, to be found again is inexpressibly exhilarating, almost a rebirth. These experiences, which touch travelers deeply perhaps because they recapitulate the terrors of childhood, may make sailors and airmen shudder in recollection, but at the same time they are an inextricable part of the adventurous life, and so they are in a way precious. All the more now, because the Global Positioning System, the satellite-based means of navigation, is fast making them extinct.

The primitive foundations of navigation are pilotage and dead reckoning. Pilotage is navigation by landmark. The earliest fliers followed rivers and roads from town to town, or, like medieval pilgrims, steered for the nearest steeple. Even the sky itself is a landscape to which a sufficiently sensitive intellect may become attuned: Polynesian “wayfinders” steered their canoes for hundreds of miles with mental sextants and visceral clocks.

Dead reckoning—some say the term comes from “deduced”—means inferring your present position from a knowledge of how long you’ve traveled, at what speed, and in what direction, from your last. This was the method used by ships before the invention of the chronometer made scientific celestial navigation possible. Dead reckoning is subject to the uncertainty of drift—the unknown component of motion owing to wind or ocean currents. The method sometimes works well—Charles Lindbergh hit Ireland right where he intended to after 20 hours over the Atlantic—but it can also fail, as Lindbergh himself later would, by errors of hundreds of miles.

Nor Dark of Night
In 1918 the U.S. Postal Service, with unbureaucratic daring, inaugurated airmail between Washington, D.C., and New York in Army-surplus Curtiss JN-4D Jennies. Because the distance was so short, the airplane’s superior speed gave it only a negligible advantage over ground transportation.

Along the New York-San Francisco route, launched in 1920, there was greater potential for saving time, but darkness was the deal-breaker. When the sun went down, pilots handed their cargo off to trains. President Warren Harding, skeptical of what he perceived to be a costly and inefficient way of delivering mail, threatened to cut off funding.

And so in the dead of the winter of 1921—the worst possible time—the Postal Service staged a bold and very nearly quixotic demonstration of fast transcontinental airmail delivery. Four single-engine, open-cockpit de Havilland biplanes took off, two from New York and two from San Francisco. One eastbound pilot was killed in a takeoff accident in Nevada, and the two westbound airplanes, halted by a snowstorm near Chicago, relinquished their cargo to trains.

Pilot Jack Knight saved airmail. Meeting the surviving eastbound biplane at North Platte, Nebraska, Knight took off in darkness. Guided by bonfires and burning oil drums that had been lit by postal employees and helpful farmers, he flew all night in bitter cold, landing to refuel at Omaha and Iowa City, and reached Chicago in the morning. A relay pilot completed the trip to New York.

Having covered 830 miles in nine hours, Knight proved that the airmail could move even in darkness and bad weather. Lionized in the press as a hero (his name probably helped), he downplayed the difficulties he had faced, though he did concede that “if you ever want to worry your head, just try to find Iowa City on a dark night with a good snow and fog hanging around.” The trail of fire that Knight followed was the beginning of the nation’s first airway system: Funded after all, the Postal Service was soon erecting electric beacons to guide night fliers along its routes.

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