Skyfaring: A Journey With a Pilot (11 page)

To the systems in modern airliners, though, magnetism is a fiction.

The distance between the magnetic and the geographic North Poles means that there are two kinds of headings a pilot may speak of:
magnetic
headings, referring to the magnetic North Pole; and
true
headings, referring to the geographic North Pole. The difference between the two, between magnetic and true, is called
declination
or more usually
variation.
Variation is not the same everywhere over the earth. In Glasgow, it is nearly negligible, at 3 degrees west; in Seattle the variation is about 17 degrees east; in Kangerlussuaq, Greenland, it is more than 30 degrees west. (Another complication is
compass dip.
The magnetic lines become vertical where they converge at the magnetic poles, as if you held a long blade of grass in your hand that was upright when it left your fist, but bent away to nearly horizontal further along its length. This means that standing at the magnetic North Pole, north is straight down, while south is directly above your head.)

Mariners were aware of variation, of course. Seafaring navigators once measured variation twice a day, at dawn and dusk, to track the local difference between true and magnetic headings. Cape Agulhas, the southernmost point of Africa that also marks the official boundary between the Atlantic and Indian Oceans, was named Cabo das Agulhas, the Cape of Needles, because five centuries ago Portuguese sailors noticed that magnetic and true north were nearly aligned here. Nowadays, pilots on a modern airliner can choose to display either type of heading. At the flick of a small switch the whole compass
rose
on our digital map will rotate left or right. It is a disconcerting moment when you first see a compass, which you imagine as a deep and incorruptible arbiter of direction, spin like a top.

Most of the time we fly on magnetic headings. The reason for this is largely historical. In the early days of aviation, pilots—like birds and mariners—only had magnetic directions to choose from, because they only had magnetic compasses. And so even today, when air-traffic controllers ask a pilot to take up a heading of 270 degrees, or due west, the controllers almost always mean not the 270 degrees that is actually west over the surface of the earth, but the 270 degrees that is displayed on a magnetic compass in that part of the world.

Yet the heading display on a 747, like that on most airliners, has no magnetic inputs. It is a surprise to new pilots, who have flown and studied and been tested on the vagaries and inherent errors of magnetic compasses, to realize that on a typical modern airliner there is nothing to sense the magnetism on the earth and feed it into the computers that generate our display of magnetic headings. There is only one magnetic compass onboard—a forlorn, technically isolated backup device that is never used in normal flight. On some aircraft it’s even hidden away, to be pulled out when needed, which is essentially never. It’s no small irony that the complicated electrical fields generated by the airliner’s systems themselves disturb magnetic compasses.

To display magnetic headings without using a magnetic compass, the plane consults its map of magnetic variation. The plane knows the pilots are not using a magnetic compass, but if they were, it knows that in this position over the earth, it would read
this.
And that’s what is displayed in the cockpit computers. In other words, the world’s airliners fly on magnetic headings derived from a preloaded map of magnetism, rather than actual compasses. If the earth’s north and south magnetic poles suddenly reversed themselves, or even if they stopped their eternal flickering one night, the pilots of commercial airliners would not see this on their screens—though birds, the pilots of small planes, and old-school hikers would notice immediately.

When I think of the long history of compasses and seafaring, or when late on autumn nights I see the northern lights, the solar wind catching in the harp-like lines of magnetism that congregate at the pole, it seems fitting that something as primeval and eerie as magnetism would have only such a ghostly sort of prominence in the shiniest machines of our age.

A further oddity of magnetism is that our elaborate fiction of it must be regularly updated. The magnetic North Pole, the star that our compasses orbit, is itself on the march—from northern Canada toward Russia, at a pace of several dozen miles per year, in a process known as
geomagnetic secular variation.
This motion means that the charts of magnetic variation must be routinely redrawn and the maps in the computers of airliners reloaded, even though nothing in the airliner’s computers can detect these changes. Runways numbered according to their magnetic direction (e.g. runway 27 points roughly 270 degrees on a compass) must occasionally be retitled too, their number-names spun, and all the airport signs remade or repainted, and all the charts onboard the world’s aircraft updated, to follow the latest twists in the planet’s old magnetic tale.

Machine

I’m at a small airfield in rural Massachusetts, aged sixteen perhaps. It’s a place that I occasionally came to with my parents when I was younger, to eat doughnuts and watch the small planes land and taxi in behind a low metal fence, the clear boundary of an airfield that many who love airplanes will have a memory of deeply wanting to cross. The planes park, the pilots and passengers get out, they walk into the lobby of the single-story building. They were in the sky; now they are here. They get into cars. They drive away, rescind a dimension, just like that.

In the lobby are a vending machine and a glass-topped counter through which I can see several shelves of maps and navigation tools for sale. On the wall behind is a bulletin board with all-capital letters stuck to it, of the type that you see in delis and diners. Here it’s a menu, too, a list of the aviation services provided at this airfield, and their prices. I know these prices by heart. I’ve been saving from my paper route and restaurant job, and now I’m here for my first flying lesson.

It’s early autumn, one of those clear, warm, bone-dry, and mosquito-free New England days, of the sort that draw people to Northern California when they realize they can enjoy them there the whole year. The leaves on the trees around the airfield perimeter are beginning to change; on the mountains nearby, as my mother would say, the color is “farther along.” I greet the instructor and purchase my first logbook, navy blue, from one of the shelves in the glass counter. We go outside and walk up to the white plane. I’m surprised to suddenly find myself on the other side of the fence.

Until today I’ve only seen planes from a distance or entered them through a jetway that masks nearly all of the experience. I’ve never touched the outside of an aircraft before. There is a surprising lightness to the plane. The doors feel flimsier than those on any car. There’s awkwardness, too, a sense that the plane is crafted for something other than motion on the ground or human comfort. There are plenty of opportunities to hit your head on something that looks expensive. The plane’s wheels are chocked, and the wings are tied to hooks in the tarmac. There must be experts whose job it is to design airfields and this must be one of the things they think of to install—hooks to tie our wings down to, when we are not in flight.

Naturally, the instructor is wearing aviator sunglasses. He is inspecting the aircraft with the seemingly contradictory mix of utter familiarity and deferential caution that I will later associate with pilots but even more so with the engineers who check and repair airliners. I follow him as he patiently explains what he is looking for at each point in his careful circumnavigation of the plane. He takes liquid from the bottom of the wing’s fuel tank, as if he is drawing blood, with a specialized tool that aspiring pilots may acquire along with their first logbook. He holds the clear column of what he has drawn up against the light, against the blue of the sky. He is checking for water. He pauses, stares straight at me. Water is bad news, he tells me. A new fact about water. Twenty years later I will read in my father’s notes that when he lived in Stanleyville, the city in the Belgian Congo now known as Kisangani, another missionary took him on a flight over the Tshopo River. Their small plane nearly crashed into the river’s reservoir because the fuel cap had been left off the night before, allowing rain into the tank.

The instructor and I have come full circle around the craft. The inspection is complete. He opens the door of the airplane and smiles, gestures, tells me again to watch my head. While I’m carefully climbing into the machine, he unties the wings.

Since I have become an airline pilot, I am occasionally asked: “What does it feel like to fly?” Perhaps the most honest answer is that I don’t know. What passengers see of the world is permanently framed by the iconic ovals, the windows cut from the hull of the vessel. Even pilots, with their wide and multidirectioned blessing of views, are surrounded by surfaces of intricate electronics, busy computer screens, buzzing radios—the plane and its permanent, metallic mediation of the experience of flight. Planes are noisy, particularly small ones. I have the sensation of truly flying, peacefully and silently as we do in our dreams, more when I’m swimming than in any airplane.

Aside from the lines that tie the wings of small planes to the ground, it’s seat belts that are the simplest reminder of the machine, of what, exactly, is flying. Whether as pilots or passengers, our experience of an airliner begins when we walk inside a contrivance the size of a building. To do what we call flying, we sit down in this. We tie ourselves to it.

Many pilots, of course, love the airplane precisely because it is a machine. An air
craft,
a root that equals strength, skill. Nor is it clear that passengers, either, wish to pretend the ship away. We might consider why photographs taken from the window seat are almost always more evocative if they include something of the airplane’s structure—an engine, the curve of the window frame, or the lines of the wing. The airplane’s photogenic presence is something more than foreground technique. Perhaps the plane stands in the imaginative place of flight itself, of the experience we cannot have directly, as if looking from the window we say: “Yes, of course, we will never fly quite like we do in our dreams. Dreams are easy; this is real.”

Machines, indeed, hardly get more difficult. Pilots occasionally experience the unusual sight of an airplane indoors. A large plane inside a hangar looks much bigger still, in the same way that even a small car suddenly appears enormous and awkward in a garage. In a hangar you see the many steps, platforms, and hydraulic lifts that are needed to return an airliner’s structure to a human scale, much as the hulls of boats are brought close to human eyes and hands in dry dock. In some hangars the plane is all but disassembled for checks and maintenance, as if an actual airplane had enacted its own
exploded view drawings,
the engineering diagrams in which parts are pulled away from each other, for the purpose of understanding or duplication.

It’s been fifteen years or so since that first lesson in a small plane over the autumn-tinged hills of western Massachusetts. I’ve been flying the Airbus for some time now. I have just finished a flight to Hamburg, during which we spoke to controllers who answer to the name of Bremen Radar. From the cockpit the captain and I saw the sun-sprayed Elbe and the beacon of the same name, which was lit on our screens and receivers. My job has brought me to Hamburg many times already. So today, instead of my usual walk along the Binnenalster Lake toward a café in the city’s old town, the captain and I are making a visit to the plant where the airliner we flew today was built.

We organized the visit only an hour before we left London. We called the factory and said: We fly the Airbus and later today we are flying one to Hamburg that was built there. One moment, said whoever answered the phone, then: Very well, what time do you land? We are treated well at the factory—vigorous handshakes, a huge lunch, a gleaming German luxury sedan—so well that we fear there’s been a certain misunderstanding, that our hosts are expecting us to sign purchase agreements, to lay down an airliner-sized deposit, before the end of our afternoon together.

The plant, a complex of enormous buildings, is an exalted place—though like airplanes themselves, a mix of the extraordinary and the humdrum. The interior volume is enormous, inhuman in its scale, yet as clean as a hospital. Some airplane factories are so large that clouds once formed inside them, a foreshadowing of the sky to come for each newborn jet. As a workplace an aircraft factory seems as inherently gratifying, as backgrounded by a general radiation of satisfaction, as cockpits are. I am struck for the first time that those who work here may have a sense of the airplane that is deeper, even, than that of those of us who fly them. The workers who crafted early airplanes were once compared to those who built Chartres. Still today, in a cathedral of industry, new vessels are taking shape; great forms are raised by the most skilled hands of our age.