Skyfaring: A Journey With a Pilot

by Mark Vanhoenacker

  America’s sky-mappers have gone to more trouble than most to ensure that local colors fly in the country’s skies. The Sonoma County airport in California is named after Charles M. Schulz; nearby is the waypoint SNUPY. Near Kansas City are the culinary waypoints BARBQ, SPICY, SMOKE, RIBBS, and BRSKT. Near Detroit is PISTN, surely for the basketball team whose name reflects the city’s heritage of industry; the skies around Detroit also feature MOTWN and WONDR (Stevie, Michigan-born) and EMINN, perhaps for the rap star. Houston’s nearby SSLAM is followed a few miles beyond by DUUNK (not to be confused with DUNKK, near Boston, a reference perhaps to a certain Massachusetts-born doughnut chain). The skies around Houston also feature ROKIT for the city’s space legacy, and TQELA, WORUM, CRVZA (beer), CARNE (meat), and QUESO (cheese) for the city’s cross-border culinary traditions that arriving passengers may soon be enjoying.

  Boston has lifted a particularly intricate constellation of itself into the ether above New England. There is PLGRM, for the region’s history; CHWDH, LBSTA, and CLAWW for its food; GLOWB and HRALD cover the city’s newspapers; while SSOXS, FENWY, BAWLL, STRKK, and OUTTT chronicle the anguishes of the city’s baseball team across the heavens. Even the region’s speech—WIKID, followed by PAHTI—seems to be mapped. There’s a NIMOY waypoint; Leonard was born in Boston. LYHTT floats above the harbor island on which stands Boston Light, the 1783 replacement of the 1716 beacon that a twelve-year-old Benjamin Franklin memorialized in a ballad. Passengers may cross the LYHTT waypoint and see this lighthouse, the first in what would become the United States and the only one that retains a lighthouse keeper, as they descend to the city it marks.

  St. Louis has the nearby waypoints ANNII and LENXX, for reasons that aviation authorities could not explain to me; perhaps it’s only that an air-traffic controller there was a Eurythmics fan. The origins of other waypoints near St. Louis—AARCH, for example, a reference to the city’s skyscraping Gateway Arch—are less obscure. Mark Twain died seven years after the first flight at Kitty Hawk. The riverboat pilot himself never flew. But Tom Sawyer Abroad features a “noble big balloon” equipped with “wings and fans and all sorts of things,” and in an 1869 letter Twain wrote that “the grand problem of aerial navigation” is “a subject that is bound to stir the pulses of any man”—reasons enough to think he might be pleased by the thought of the sky place TWAIN, above Hannibal, his childhood home on the Mississippi.

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  As a sequence of places—beacons, waypoints—a route becomes its own kind of place. In the Japanese language there are many counter words to enumerate conceptually similar kinds of objects. English, as instructors may point out to students of Japanese, has a few such analogous words. We say three loaves of bread or two sheets of paper, so loaf and sheet are our counter words for bread and paper. We think of sheet as a concept of form and apply it to many flat things such as aluminum and pastry. One’s favorite counter is a regular topic of conversation among foreigners studying Japanese. I’ve always liked 本, hon—perhaps because it is also the hon in 日本, Nihon or Nippon, Japan, the destination of my high-school summer homestay and some of my most memorable subsequent journeys, first as a consultant and later as a pilot. As a counter, 本 is used for long, cylindrical objects such as pencils, films, roads, and rivers. 本 can be used to enumerate air routes. Contrails, too.

  The exact route a plane flies between two cities often changes. Airways are pre-published lists of waypoints and navigation beacons, crossing steadily over the undisturbed and uncharted fields and forests and rivers below. Flight planners and pilots choose among the various airways that can link two cities, accounting for the wind, airspace closures, congestion, and navigation charges imposed by overflown countries. One path intersects another, and a flight plan will often jump between airways at these junctions, tacking a wind-optimized path over the earth. Other routes, like those over the North Atlantic, are drawn anew each day by air-traffic authorities, to reap the most of tailwinds or the least of headwinds. In some parts of the world there are few or no formal airways, nor wind-sculpted schedules of daily routes. In such open sky country flight planners are free to compose their own route each day, from raw points of latitude and longitude—digital fictions in the ether that the broad sunlit wings of a high 747 will overfly long after the planner has returned home, eaten dinner, turned the lights off, and gone to bed.

  Often the technical precision of routes barely conceals their historical and cultural resonance. The daily routes over the North Atlantic are typically called the tracks, a general term for the thick, highly trafficked belt of routes between Europe and North America, and a daily refrain to the bonds—of exploration, empire, language, trade, culture—that run as deeply as ever across these waters. Over Africa, the predominant flow of traffic is traditionally from north to south, but during Islam’s Hajj pilgrimage, a huge flow of east–west air traffic briefly arises, crossing northern Africa toward Mecca, a season of the air that is an echo and a reversed image of the historical flow of Islam itself. There are special Hajj charts and procedures, issued each year to pilots who will be crossing North Africa at that time.

  Not long ago we switched from mostly paper charts to mostly electronic ones, stored on tablet computers. The paper charts we used until recently, though falling out of technological favor, are more interesting, because their designers could not place everything on them, nor could pilots simply select different layers of information to display or hide. The choices required by the mapmaker reveal much about the geography of the sky. The paper charts show airports, but not the cities they correspond to. They don’t show roads, or the earthbound borders of provinces or states. Mountains are unnamed and exist not as peaks or contours on these charts but as generalized heights for an area. Even the names and borders of countries are not displayed prominently. The most obvious features on these paper maps are complex networks of dark lines, the routes that link waypoints, the highways of the aerial world.

  Even the cut of the paper follows routes, which follow history. Most ordinary maps—those in a typical atlas, for example—appear to be rectangles lifted directly from the earth. The top of the map is roughly north, the bottom south. But the rectangular en-route paper charts are often not aligned this way. In their off-kilter calibrations we see the deep axes of empires, migration, and the whole of human geography, as clearly as the archaeologists who made some of the earliest uses of aircraft, to discern man-made patterns on the earth. For example, the paper maps that a pilot may follow from Europe to Hong Kong are not oriented to north. Instead they are cut in long, great-circling arcs that roughly echo the typical routes between Europe and China, so that the left edge of the rectangular sheet faces northwest, and the right edge faces southeast. Over central and northern Canada a series of charts runs in a similar but more sharply tilted orientation that only makes sense in the context of the air links between eastern North America and East Asia.

  Routes often have a personal weight. Frequent travelers over the North Atlantic, for example, will have an intuitive sense of just what the plane connects; the cultural and historical bridge that each of their own journeys reflects and renews. The first time I flew across Australia, from Singapore to Sydney, we made landfall on the country’s northwest coast, near Broome. Then we followed a series of long airways that arced across the continent toward the southeast. The distant lights of Alice Springs reminded me that I had first read this name in a Hardy Boys story that hinged partly on the revelation that this overheard name was a reference to a place and not a person.

  As we crossed the outback it was hard not to think of song lines—of not just the route in the computer but of how everyone onboard might imagine the line of space between the paired cities, our individual assemblies of mental and physical geographies. For passengers a route exists in the moving map on cabin screens, but also in their understanding of how two particular cities differ and why they are flying from one to the other, and of what stands or floats between them. Most of the Australia
ns onboard that night would surely have had a deeper sense of the route than any foreign pilot flying over it for the first time.

  Eventually, routes become familiar to pilots, and then the passage of landscapes, sky regions, or beacons give journeys between two cities a unique pace. Pilots will acquire this background sense of the progression of a route just as the conclusion of one song on a beloved playlist leads you to anticipate the next; or as you might intuitively and almost unconsciously travel along the series of landmarks that guides you to a friend’s house and from there to the supermarket and from there back to home. The sky regions, for example, pass in as orderly and ordinary a fashion as the sequence of towns on a car journey, marked by welcome signs along the road. We might sense our progress northeast from Houston, say, as the rhythm of the sky realms Houston, Fort Worth, Memphis, Indianapolis, Cleveland. A flight from Arabia northwest to Europe traverses Jeddah, Cairo, Hellas, Tirana.

  When I fly from London to Los Angeles, first is England, of course, much of which has already passed by before a heavy 747 reaches its first cruising altitude. Next are Scotland’s great cities, Edinburgh and Glasgow, which always appear on our computer, but rarely, given their typical weather, in the window itself. Then there’s Stornoway, in the Outer Hebrides—there is a beacon there, and to cross it feels like an aerial Land’s End, the sky tip of Britain—and then if I can see the water I may remember the song I love by Karine Polwart, about the sea off Scotland, where “the waves swell like a barley field that’s ready to lay down.” Next, perhaps, are the Faroes, though not every route goes near them and they are shyer, more cloud-veiled even than Scotland; I have only seen them a few times.

  Next Iceland’s mountains and glaciers appear as digitized bumps on the screen, and occasionally in white, outside the window. Then sea, and perhaps night itself this far north, depending on the season, and Greenland, which is often brilliantly clear. After Greenland comes hours of white over Canada, a wilderness that eventually fractures into fields and roads and other sensible or familiar ideas. We cannot see the American border itself, but we overfly Interstate 90, the easy-to-spot road that runs clear across the continent between Seattle and Boston.

  Then, if I am approaching Los Angeles from the northeast, come the Rockies, and road-etched deserts, and more mountains before the city waiting beyond, on the sea. If, however, I arrive from the north, I can count off the landmarks of America’s snow-fired ring of prominent volcanoes: Mount Baker, Mount Rainier, Mount Hood, the sky-blue caldera of Crater Lake, and soon enough the snowy, stand-alone slopes of Mount Shasta, America’s Fuji, which dominates the skies of Northern California and is said to be inhabited by the spirit of the Above-World, an assertion that few who see it, whether from below or above, would bet against.

  Such geographic mileposts echo in the airplane, and even in the mundanities—sleeping, eating—of a pilot’s life. The timing of our rotating breaks means that changeovers usually take place over roughly the same parts of the earth. On many routes between London and western North America, for example, Greenland’s mountains roughly correspond to the first changeover, and so the mountains, approached from the east, are to me associated with leaving the controls to go to the bunk. Similarly, they are what a pilot returning to duty expects to see crossing the windows of the cockpit when the other pilot, reminded by the sight of white peaks rising from blue sea, has gone off to rest.

  Food, even, mirrors the pace of the turning world. Places in the sky take on the quality of a clearing at the bend of a hiking trail where I stop to eat lunch, marking a particular and regular point in the journey and my appetite. When I imagine Las Vegas, how it looks from the air, I think of it as a quiet spot in the sky that I associate with sandwiches and coffee, because it’s where—or when—I often have a snack before the busy descent into Los Angeles begins.

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  I’m a student pilot, near the beginning of my flight training in a small single-engine plane. I’m flying alone, somewhere northeast of Phoenix. I’m lost.

  I am navigating, or trying to navigate, visually. I have a detailed chart that depicts mountains, roads, settlements, radio masts. I match what I see on the world below to the chart, and what the chart leads me to expect next I match onto the world, back and forth, back and forth, between the two. But the afternoon has grown much hazier than forecast, and for the first time I experience one of the effects that can suddenly make this kind of visual flying difficult. I can see straight down through the haze, but anything even slightly ahead or to the sides is obscured, an effect familiar to anyone who has ascended a skyscraper on a misty day.

  A pit forms in my stomach when I realize I can no longer connect anything I see through the small window of visibility below the plane with anything on the map inside the plane. I work again from the last position I was sure of, and the minutes that have passed since I was sure of it, a rough calculation that suggests a time-dependent circle I must be somewhere on. But soon this ever-expanding circle will meet mountains, the jagged, sandstone-colored peaks hiding somewhere to the northeast of me in the haze. Hardly less worrying is the strictly controlled airspace around the international airport in Phoenix, from which my intended route would have kept me well clear.

  I am about to call a controller for assistance, who would give me a code for the onboard transponder that would help the controller steer me home. Then I remember that there is a navigation beacon right at my home airport, in the eastern part of the Phoenix area. My instructor taught me to use such beacons weeks ago, almost casually; it was certainly not part of the lesson plan for this kind of flying. “Just in case,” he winked. I dial up the beacon. It flickers to life. I exhale, then follow the needle like a trail of electromagnetic breadcrumbs through the day’s unforecast murk. I turn sharply right and descend through the haze, and soon I see the runways ahead. I rest my hand on the top of the dashboard in relief and thanks, and then I land.

  How do pilots and planes know where they are? It’s an excellent question, but one I am almost never asked now. The assumption is that GPS answers it, though small planes, like the one I flew in Arizona, may not be equipped with GPS receivers. Most airliners now make use of GPS. Often, it’s been added onto an airliner that was not originally designed for it. There are many such technologies—related in particular to communications, and to the avoidance of other aircraft, wind shear, and mountains—that accrete in aircraft systems as layers of progressively higher neurological functions evolve in living organisms, while older systems still twinkle in the lower-down layers.

  One of these older systems is inertial navigation. It ensures that the airliners of the world could find their way home on the darkest and cloudiest night, even if all the GPS signals, air-traffic control centers, and ground beacons fell silent.

  Imagine you have been blindfolded in a stationary car. Then you feel the car accelerate to roughly highway speed. After about an hour, you might guess you were 60 miles from where you started. Then, if you felt the car turn by 90 degrees or so, before driving for another half an hour, you could draw a triangle and have a further guess as to where you were. Similar to the vestibular system in our ears, an inertial navigation or reference system senses these two qualities: acceleration and rotation.

  Acceleration is measured by accelerometers, which are relatively simple devices. To accurately measure rotation, inertial systems use gyroscopes, which are anything but straightforward. Originally mechanical (a spinning top, one of the world’s older toys, is a basic gyroscope), the gyroscopes in modern airliners most often use light rather than spinning discs or wheels.

  The name given to such a light-based tool for measuring rotation is ring laser gyroscope. We think of laser beams as the very definition of straight. A ring laser gyro forces such a light beam into a closed path. Imagine a cube of glass with a tunnel drilled into it. The tunnel turns corners, forming a perhaps triangular light-course in the glass. At one point in the glass tunnel, light is fired in both directions. The beams trave
l around the loop with the help of reflectors, before meeting on the far side of the tunnel. If the device has not been rotated, then the beams arrive at the same time on the far side. But if the device has been rotated, then one beam will travel a slightly longer path through space, and arrive slightly later than the other.

  A rough analogy is to imagine a round, frictionless billiards table (indeed, gyroscope means “circle watcher”). If you roll two balls away from you around the edge of this table, in opposite directions, toward a friend standing across from you, they’ll reach your friend at the same time. But if you start to rotate the entire table after you have rolled the balls, one will roll for a longer distance, which takes a longer time. It will arrive at your friend later.

  Isak Dinesen wrote that language “is short of words for the experience of flying, and will have to invent new words with time.” The terminology of aviation is occasionally clumsy—we often speak of the brakes we use in the air as speedbrakes, for example, as if there could be any other kind. But the language of inertial systems is a high sort of technical verse, the engineering equivalent of Petrarch. The designers of these light-boxes speak of the body frame, the local level frame and the earth frame. They deal in gravitational vectors, the transport rate, the earth rate, and days referenced not to the sun but to sidereal time, the rotation of the planet against the background light of distant stars. The engineers responsible for inertial systems talk of random walk and coasting, northing and easting, and the spherical harmonic expansions.