Skyfaring: A Journey With a Pilot (15 page)

The tires themselves are so comically large—around 4 feet in height and a foot and a half in width—that perhaps only a child would size them correctly in a sketch. Each 747 tire may be rated to bear a load of 25 tons, as much as the monstrous tires of some earth movers, which do not have to land on them or hurtle down a runway on them. Often the speed limit of aviation tires—235 mph, for example—is written directly on them, along with “AIRPLANE,” as if to warn against the insult of their installation on a less exalted sort of vehicle. It is hard to imagine these wheels later, unchocked, unleashed, blurring to the speed of takeoff. As the wheels are retracted the brakes will bring this rotation to a halt, so much turning turned to the heat that will be carried for many hours across the high cold sky. The end of the flight brings the sudden return of speed. The wheels are not turning when they hit the ground, but must be spun up once again at touchdown, more or less instantly, to the speed of the flying earth. Long after parking, the rubber of the tires is often still warm to the touch.

Walking around the aircraft wheels, I feel occasional gusts of the last flight’s heat, its enormous, braked speed, drifting off in the breeze. The shock of a jet engine, in contrast, is that it is already so cool. We may not often think of engines in day-to-day life; perhaps we take them for granted or find them dirty or low, as if they were a brief necessity during a former stage of history, that we had no choice but to cross in order to reach this age of information. But even now, in the realm of endeavor that we have named
engineering,
aircraft engines—comparably unconstrained by cost, sculpted by air—are among the most impressive creations. Clean-lined tubes of enormous, refined power, hanging from the stately wings of airliners, the everyday word
engine
—
ingenium
in Latin, meaning talent, nature, clever contrivance—catches in the light of its origin.

Picasso—one of whose paintings would be onboard an airliner lost off Canada in 1998—used to address the French artist Georges Braque as “My dear Wilbur,” in an affectionate reference to the imagination and artistry of the Wright brothers. Marcel Duchamp, at an early exhibition on aviation, famously turned to Constantin Brâncus¸i and said: “Painting is finished. Who can do anything better than this propeller? Can you?”

Aircraft propellers are beautiful things. It was the Wright brothers who realized they should be understood not as aerial versions of maritime propellers, but as rotating wings (indeed, airplanes and helicopters are sometimes distinguished by the terms
fixed-wing
and
rotary-wing
). Yet propellers have their limitations. The tips of the blade spin faster than the inner portions, a consequence of physics that explains the effectiveness of salad spinners. But when propellers get very large and fast and the blade tips approach or exceed the speed of sound, their efficiency declines dramatically.

I have always been more fascinated by jets. To watch jet engines in flight is still a treat to me in the passenger cabin; especially from the rear cabin of the 747, where the scale of both the engines and the wings is most apparent. On the largest versions of the 777 the engines alone are comparable in diameter to the fuselages of many airliners. They conjure the speed that gives the wings life, that gives us flight. Yet they work without apparent motion or effort, unless you can see the turning fan, or unless you see the light from the setting sun fall on a portion of the wing, flickering and scintillating after it has passed through the churning column of thrust behind an engine. A jet engine at takeoff looks more or less the same as one shut down on the ground or sitting in the corner of a factory; a grace of engineering and air so purely channeled that the mechanism itself is all but unseen.

The engines are identified in our manuals:
three rotor axial flow turbofans of high compression and bypass ratio.
First comes the gyral memory of watermills or crank-started motorcars, when we begin to
turn the engine.
Then, when the
start cycle
is complete, and the engines are
stabilized at idle,
we
advance the thrust levers.
At the front of the engines is the alloyed carnation of the fan. The blades stand as perfectly round as the dashed markings around the edge of a railway station clock. On airliners smaller than the 747 it is easy to reach the blades to check for ice, fingering their surprising backs, the unseen surface of the gleaming spokes. The excited five-year-old in me may give this fan a casual, affectionate whirl, and it is difficult, too, to believe how easily such a vast wheel can turn. The blades themselves are cool to the touch and, despite the name, are not sharp. On one version of the Airbus that I flew, the blades of the fan rattled when I spun it. Only at high speed would the blades hurl themselves out like the riders on a fairground ride, summoned by rotation to their appointed positions.

The underwing location of the engines on most jet aircraft gives rise to one of the more curious aspects of flying them. Imagine a cardboard outline of the plane, loosely fixed to a bulletin board with a pin, free to rotate. If the engines are below the plane’s center of gravity—i.e., if they are hanging from the wings—then when power is added, the plane rotates around the pin. The nose rises, and the tail falls. This effect, the
pitch-power couple,
results in some counterintuitive flight maneuvers. For example, when we abort a landing and climb rapidly upward, we add power and pull back on the control column to bring the nose up. But as the thrust increases, as the engines
spool up,
the pitch-power couple quickly becomes so strong that we must reverse our inputs and start to push down on the control column even as we wish to continue climbing. This need to steer against power changes feels something like the steering torque that sometimes pulls a powerful car to one side when you accelerate rapidly. On some newer airliners the flight computers counteract the pitch-power couple automatically. Pilots on these aircraft must then in effect set aside one of the more eye-opening aspects of flying underwing-engined aircraft that they went to some trouble to learn.

From behind the engine you can see the
core,
the engine within the engine.
Core
is the right word for these hidden and essential machinations. To be so close to the stilled engine is like visiting an empty stage before a performance or walking down the middle of an avenue temporarily closed to cars. Steinbeck wrote about how “the sound of a jet, an engine warming up” could induce the “ancient shudder” of his wanderlust. Here, up close, is what makes that sound; what, exactly, warms up. Once the plane takes off, the space immediately behind the engine will be flooded with unimaginable speed and heat, easily 900 degrees Fahrenheit, spinning out as if from a ship’s propeller into the icy vertical miles of nothing.

When I first looked closely at airliners, I was struck to see that national flags sometimes appear in mirror image on them—so that on the right side of an airliner the block of stars on an American flag is in the top-right rather than the top-left corner, on an Australian flag the stars of the Southern Cross shine on the left rather than on the right, and on a Singaporean flag the crescent moon appears to be waxing rather than waning. The idea, which appears in other contexts, such as the shoulder patches of soldiers, is that this is how even an image of a flag should fly as a vessel sails forth.

The sight of such flags is a reminder of the many ways an airliner answers to the air even before it moves. Often on a parked jet you find the blades of the engines are already rotating. Strong but light, built for air and the smoothest turning, they catch the slightest breeze and spin with the insistent nonchalance of a lawn mower. The things we have made, our air wheels that rest most easily in motion.

From inside the terminal on a windy day, the depowered rudders—the vertical panels at the back of the tail—of a row of parked planes may all be hanging to one side, blown all in the same direction like the branches of a line of windswept trees. The tail, which looks like a sail, acts like one, too. To counteract a crosswind blowing from left to right as we accelerate for takeoff, we must steer not toward the left, as you might think, but toward the right; the wind catches on the vast tail and rotates the nose
into
the wind, a phenomenon known as
weathercocking.
If you board a plane on a breezy day, you may feel it gently rocking back and forth before you leave the gate. That is mostly the tail, catching the wind.

Planes must occasionally be weighed, to ensure that calculations of the power required for takeoff, for example, are correct. This weigh-in takes place in a hangar, the doors of which must be kept closed, because even a light afternoon breeze on the wing will cause it to work a little, to soar ever so slightly, and tug the craft away from the scales of the earth.

—

It’s October 2007. About a month ago I flew my last flight on the Airbus. We pushed back from Newcastle at 09:22, and parked at Heathrow just under an hour later at 10:21. Below that line in my logbook I switched to a different plane and a different color of ink. In the weeks since that flight I started my 747 type rating and now I’ve completed the classroom training portion and various exams. Today I’m entering the cockpit of a 747 for the first time. But there’s only a cockpit. There’s no plane attached to it. It is a box, surrounded by banks of screens, perched on jacks in a cavernous room. This is a full-motion flight simulator. Today I start the simulator sessions; I’m virtually flying. My first flight on the real airplane is already scheduled, for about a month from now: London to Hong Kong.

Though the simulator’s wraparound video screens do an admirable job of conjuring up the cockpit’s expansive views of the world, the simulator must also simulate the blindnesses that are a striking feature of flying a large airliner. The plane is so high, and the nose so rounded, that we cannot see anywhere underneath or immediately ahead of the plane. When we are taxiing, the knowledge that there is nothing under the nose of the plane in a given area comes solely through having seen that area before.

From the cockpit we cannot see anything behind us. When giving taxi instructions, air-traffic controllers must take account of this. For example, they may ask us to inch forward to allow an aircraft behind us to make a turn, the kind of maneuver that might occur naturally between courteous drivers with their rearview mirrors. On some airplanes the pilots can see nothing of the wings. From my seat on the 747, I can see only one of the four engines and a small portion of one wing, and even these only with difficulty.

Nor can we see the wheels, some of which are 30 yards or so behind us, or the tail, a further 40 yards or so behind them. This unseen length, and the enormous wingspan, means that maneuvering on the ground can be more challenging than flying. It’s like walking while carrying long planks of wood: you must adapt your sense of size and shape and consider beforehand how you will move and turn. Sometimes a controller asks us to report when we have left a runway, and we must remember that while we, in the cockpit, have left the runway area, nearly all of the rest of the plane behind us has not. In aircraft manuals, elaborate charts that recall da Vinci’s
Vitruvian Man
show the angles and distances that the extremities of the plane sweep when the plane turns on the ground. A pleasing terminology accompanies these images of the plane’s turning limbs:
tail radius
and
steering angle,
and the wingtip that
swings the largest arc.

As much as possible this physical reality must be mirrored by the simulator. A taxiway light ahead will come toward me, then disappear under the nose. A certain distance, a certain speed-dependent time later, the simulator will shudder as the virtual wheels hit the same virtual light.

Pilots may jokingly start a reference to a bygone era of aviation with the phrase: “Back when Pontius was a pilot…” When I hear this it is hard not to remember that the cockpit screens that condense information about the far-flung ends of those airplane-spanning wires are often called
synoptic displays,
or the
synoptics,
a term that means “seeing-together” and that may remind us of
synopsis,
or the Synoptic Gospels, the accounts of Matthew, Mark, and Luke that represent three takes on roughly the same events. There is a synoptic for the landing gear, which displays the tire pressures, brake temperatures, and the positions of the gear doors, and another synoptic for the air-conditioning, and so forth, for each of the major categories of systems.

On an older aircraft like the 747, the computerized maps on our
navigation display
are surprising for how little they show. Typically a pilot looks only at the waypoints that will be crossed in the next quarter of an hour to one hour of flight, and perhaps a few nearby airports and radio aids.

What is not displayed on the 747—what the cockpit computers do not even know about—is nearly everything else that might appear on any other kind of map. The cockpit’s computerized map does not show the locations or names of a single city, state, province, or country. It does not show anything so lowly as roads or railway lines. It does not specify whether the ground is covered by forest or desert, or even whether it is ground at all, rather than a lake or glacier. It does not know of rivers. Even mountains are generalized into unnamed blocks of forbidden air; not features of the earth so much as failures of the air; aberrations in the purity of sky. There’s no concession to the general-interest user or the geography lover, no flair or artistry, no Elysium or sketched dragons lurking along the edge.

In the cockpits of these vessels that round the planet, there’s no way to zoom out far enough to see the curve of the earth, an increasingly common feature on the moving maps viewable by passengers. Although once a colleague on the Airbus showed me a convoluted method to conjure a waypoint on the opposite side of the world. When I was first shown this trick, we were over northern Germany and our antipode was in the Pacific, somewhere southeast of New Zealand. Once such a waypoint is plotted, if we’ve done it right, it will appear on our screen, as if we are looking through the center of the plane’s spherical idea of the earth. This mark of our opposite location then moves
up
the moving map, a strange sight on a screen where everything else affixed to the earth—airports, beacons, mountains, whatever’s on this side of the sphere—moves down.