Aloft
Page 5
But the use of that tool is not as obvious as it might at first seem. The artificial horizon is a gyroscopically steadied line which stays constantly level with the earth’s surface. The airplane pitches and banks in relation to this steady line, which in spatial terms never moves. The problem is, in airplane terms it does move. And pilots are part of the airplane – they fly it from within, strapped to their seats, sensing like the Marquis d’Arlandes their own full bellies. In clear skies they would never misjudge a bank as the tilting of the earth, but with their view restricted to the abstractions of the instrument panel they sometimes do just that: They perceive the airplane’s lateral motion as a movement on the face instrument of the artificial horizon line. This causes them to ‘fly’ the wrong thing – the moving horizon line, rather than the fixed symbolic airplane. For example, as turbulence banks the airplane to the left, the pilots, banking with it, notice the artificial horizon line dropping to the right. Reacting instinctively to the indication of motion, they try to raise the line as if it were a wing. The result of such a reversal is murderous. Pilots steer to the left just when they should steer to the right, and then in confusion they steer harder. While maneuvering calmly inside the clouds, I have flown with students who for this reason suddenly tried to flip my airplane upside down. They were rational people, confronted by the turn.
This has become a basic reality of our time. We are the energetic, self-centered, adaptable species, carving a landscape of motion through the sky. If we try to fly by instinct through the weather, even the best of us will roll into spiral dives. If we misread an artificial horizon, or follow one that has failed, we will take a shortcut to the same destination. The circumstance that causes the spiral is the very circumstance that prevents its solution. The bank itself cannot be felt. Pilots experience the fury of the dive and die in confusion. That is the inside history of human flight. The Montgolfier brothers gave us the balloon and introduced us to the peculiar egotism of flight. The Wright brothers gave us the wing and confronted us with the dilemma of the turn.
The Wrights flew straight and level at Kitty Hawk, North Carolina, on December 17, 1903, and a bewildered press paid little attention. The flight was the culmination of an almost incredible four-year story – two unassuming bicycle builders engaged in a process of problem solving so sure-footed that it left the world behind. The Wright brothers were simply smarter than their peers – much smarter. If their insight was to understand the importance of flight control, it was only with the mastery of the bank that they achieved their purpose. After their initial straight-ahead runs, they went home to Ohio, rented a cow pasture on the trolley line outside of Dayton, and spent the following year stretching their flights and learning to turn. At a time when higher authorities continued to proclaim that such acts were impossible, deep in the American countryside there were a few farmers who came quietly to know that the Wright brothers could fly.
The first detailed account of the Wrights’ success appeared not in the New York Times or the Scientific American, but in Gleanings in Bee Culture, a little magazine for beekeepers published in Medina, Ohio. The editor and publisher was Amos Root, a typically moralistic Midwesterner with a taste for practical technology. In an aside intended as a parallel to the Wrights’ experience, he admitted that as a young man he had imported the first modern bicycle to Ohio.
The whole town jeered at me, and the story of the ‘fool and his money’ was hurled in my teeth so many times I almost dread to hear it even yet. Men of good fair understanding pointed their fingers at me, and said that anybody of good common sense ought to know that that thing would not stand up with a man on it, for that would be an utter impossibility… Finally I rented the largest hall in the town, went in with one trusty boy who had faith, for a companion, and locked the door. After quite a little practice on the smooth floor of the hall I succeeded in riding from one end to the other; but I could not turn the corners. When, after still more practice, I did turn one corner without falling, how my spirits arose! A little later I went in a wabbly way clear around the room. Then my companion did the same thing, and, oh how we did rejoice and gather faith! A little later on, with a flushed but happy face, I went out into the street and rode around the public square.
Thirty years later now, Amos Root had a car, which he drove 350 miles round trip to visit the Wrights’ cow pasture near Dayton. There on September 20, 1904, he happened to witness Wilbur fly the airplane’s first full circle.
Bees, of course, are the great specialists of full-circle flying; they spend their days on round-trip missions and construct whole landscapes out of their ability to turn. Root must have been influenced by that knowledge. It is clear that he felt a general enthusiasm for circular movement, which meant that he of all people was predisposed to appreciate the significance of the flight that day. He labeled it ‘the first successful trip of an airship, without balloon to sustain it, that the world has ever made, that is, to turn the corners and come back to the starting-point.’ And he was right. It is the turn that makes the airplane practical.
The U.S. Army was slower to catch on. Five years later, after much convincing by the Wrights, it reluctantly took delivery of its first airplane. In 1909, horses still seemed more glorious. The war in Europe changed that. By its end in 1918, the cavalry had been slaughtered, and flying was all that remained of chivalry and adventure. Unsullied by the carnage in the trenches, pilots chased across the sky, turning hard on each other’s tails. The war taught them to fly with confidence and encouraged among them the myth of inborn ability. They called it flying by the seat of the pants.
As in all wars since, more pilots died by error than by enemy action. Those who died in spiral dives left no records. Those who survived made the dangerous discovery that people can feel at home in the sky. They learned to accept the strangeness of a steep bank – the G-load and the sight of a tilted horizon – and the magic of a full roll. Nonetheless, they still believed in balance. When they ducked through small clouds and emerged with their wings slightly tilted, they did not suspect the importance of the unfelt bank. Luckily for them, when the weather was bad, or on black nights, they waited on the ground. German pilots called good conditions ‘flight weather,’ because they could fly, and bad conditions ‘flier’s weather,’ because they could stay in bed. By happy coincidence, pilots had no reason to fly when they had nothing to see.
After the war, regular airmail service started in Europe and the United States. It made airplanes useful to the public for the first time, gave birth to the airlines, and placed pressure on the pilots to operate on schedules. They followed rivers and railroads in open cockpit biplanes with no gyroscopic instruments and flew under the weather, sometimes at extremely low altitude, dodging steeples and oil derricks.
One of those early airmail pilots, Dean Smith, wrote about getting his first route briefing for a bad weather run, west across the Allegheny Mountains to Cleveland:
From the field here at Bellefonte you head west through the gap in the ridge. Climb as you veer a bit north, passing over the center of this railroad switchback up the side of Rattlesnake Mountain, then due west again to clear the top of the ridge at, say, 2,200 feet. After about ten miles you hit the railroad again at Snow Shoe – look sharp, it’s only four or five houses – then follow the railroad on down to the other side of the Rattlesnake to the valley where you pick up the West Branch of the Susquehanna River, winding along to the town of Clearfield, which you will know by three round water reservoirs just south of town. Next, you have to get over about thirty miles of plateau to Du Bois. This is pretty high, about 2,200 feet, but it is fairly smooth on top and there is a white gravel road cut through the trees straight to Du Bois. As you come into town you will see the railroad to your right, and just south of the railroad a piece of flat pasture you can land on in a pinch. Then the highway leads you for fifty miles through Brookville to Clarion. Each of these towns has a half-mile race track. The one at Clarion is half full of trees, but the one at Broo
kville is clean and hard, and it’s the best emergency field from here to Cleveland: as soon as you land you will be met by a girl named Alice Henderson, driving a big Cadillac, who will be pleased to look after you. After Clarion, the country gradually gets lower until you cross the Allegheny at Greenville, which you can identify by a big S bend in the river. From then on it’s clear sailing.
After such a flight, no one could accuse a pilot of not having ‘been’ to the mountains. Many were killed for the attempt; in fact, the early airmail flying was the most dangerous flying the world has ever known. But still the globe refused to shrink. Fog, night, and heavy weather continued to ground the airplanes. Some pilots did have a rough, though technically uninformed, respect for the disorientation lurking deep within the clouds, but most pilots simply stayed below the weather. In pride and ignorance they told themselves that this was because without radio navigation they needed to see landmarks to find their way. It was another happy coincidence.
In the winter of 1925, a young Army pilot named Carl Crane got caught in the clouds at 8,000 feet directly over Detroit while trying to fly a congressman’s son to Washington, D.C., in a biplane. Crane later became a famous master of the turn. Speaking of the flight, he said,
In a short time, I was losing altitude, completely out of control. I could not fly the airplane at all – it had gotten into a spiral dive. Half way down I looked around at my boy in the back, and he was enjoying the flight no end. He was shaking his hands and grinning, and I was slowly dying because I knew we were going to crash.
The boy in the rear cockpit was just unaware. Crane had an altimeter and airspeed indicator. He thought he was dying ‘slowly’ only because of the way experience is compressed when an airplane goes wild. Pilots then tend not to think about God or their lives but about solutions. Once when flying a series of ill-considered acrobatic maneuvers, I stupidly lost control of an airplane and started into a flat spin – a dangerous condition from which there may be no recovery. On that particular flight a video camera had been mounted behind me in the cockpit, and as a result I later saw the whole thing on tape: the nose rising unexpectedly, the forested horizon swirling, and the uninformed attempt to find the answer – the systematic control stick motions, the experimental bursts of power, the reach for the canopy jettison knob, the inexplicable return to normal flight. The experience was frightening, even though I was wearing a parachute and flying in the clear. But what surprised me most about it later, when I saw it in on the tape, was the speed with which it was over.
Carl Crane’s loss of control, which was both more dangerous and more prolonged, must have seemed at the time to stretch on for an eternity. Neither he nor his passenger was wearing a parachute. From his training he remembered only vague admonitions to stay out of the weather. But he was in the weather now and couldn’t see a thing. He knew he was turning but could make no sense of the compass. It is a notorious problem: Because the earth’s magnetic field does not lie parallel to the globe’s surface but dips down toward the magnetic poles, the compass card responds to banks by spinning erratically, jamming, and sometimes showing turns in reverse. Crane did not know which wing was down, let alone by how much. If he tried to level the wings, he was just as likely to roll upside down as right side up. If he tried to raise the nose, the effect would be to quicken the turn and steepen the dive. Crane understood none of the details at the time, but he sensed that his situation was hopeless.
Dean Smith, the early airmail pilot, had gone through a similar experience. His memoir of a weather flight, written thirty years later, still rings with the authentic confusion of the time:
Now followed a long period of fighting to keep control of the plane while all the time my equilibrium became steadily more confused. I succeeded in climbing to 8,000 feet; then the plane began to get more and more out of control. It lost altitude until I was back down to 5,000 feet… At last I fell. The plane stalled and whipped off into a spin, although to my bewildered senses it did not seem to be spinning down, but impossibly up and to the side. I cut the throttle and held the plane in the spin for a few seconds to be certain I was in a known condition and to force my mind to reorient. When I broke the spin, I couldn’t pull out level from the resulting dive. By the time I got the wires to stop screaming the plane promptly stalled again. The plane floundered through the dark muck in a series of stalls, spins, dives, and pull-outs. I struggled and fought with it all the way down, working with desperate concentration, but that little corner of my mind that detachedly views such things said, ‘My friend, you are a dead duck.’
Dean Smith happened to survive, but others even today do not. The physics have not changed. In modern times, air traffic control recorded the radio transmissions of an unskilled pilot who, with family on board, tried to descend through an overcast. After he lost control, he began to sob into the microphone, begging the radar controllers to tell him which side was up. But radar shows air traffic as wingless blips on an electronic map, and is incapable of distinguishing banks. Controllers are in the business of keeping airplanes from colliding. Pilots are in the business of flight control. This one had instruments on board by which he could have kept his wings level, but in the milkiness of the clouds he became confused. The controllers listened helplessly to his panic and, in the background, to the screams of his children. The transmission ended when the airplane broke apart, somewhere far away inside the sky.
But Carl Crane’s biplane – over Detroit in 1925 with the congressman’s son – was stronger:
Finally it got down to under a thousand feet, and I said, ‘Well here we go. I’m going to look at my boy once more.’ And as I turned around to look at him, a sign went by my wing. It said ‘Statler Hotel.’ I had just missed the top of the Statler Hotel. In all the mist and rain, I could see the buildings and the streets. I flew down the street and got over the Detroit River, and flew down about ten feet high all the way to Toledo, shaking all the way.
Crane became obsessed. Shocked by the way intuition had abandoned him, he began to ask questions. For years he got no intelligent answers. He never met Dean Smith. Those veterans he did meet kept insisting they could fly by the seat of their pants, and they thought less of those who could not. Their self-deception now seems all the more profound because the solution – a gyroscope adapted to flying – was already widely available.
The gyroscope is a spinning wheel, like a child’s top, mounted in gimbals that allow it freedom of movement. It has two important traits: Left alone, it maintains fixed orientation in space (in relation to the stars); and when tilted, it reacts in an odd but predictable way. Elmer Sperry, the great American inventor, started playing with these traits in the early 1900s. As a curiosity, he designed a gyro-stabilized ‘trained wheel barrow,’ and he tried, without success, to interest a circus in it. Undiscouraged, Sperry turned to the U.S. Navy instead and interested it in gyro-compasses and ship stabilizers. Competitors in Europe developed similar devices and during the buildup to war interested their countries’ navies, too.
Airplanes were an intriguing sideline. Sperry built a gyroscopic autopilot in 1910, not to enable blind flight but to stabilize the otherwise unruly early flying machines. In 1915 he began to ponder instrumentation and with prescient insight into the problems of flight was able after three years to produce the first gyroscopic turn indicator, an instrument still in use today. Its face consisted of a vertical pointer, which indicated turns to the left or right. (Necessarily, it also included a ball like a carpenter’s level, an inclinometer that showed not bank but ‘skid’ or ‘slip’ – conditions of lateral imbalance.) Sperry called the instrument a ‘crutch to the compass.’ In his patent application he described its use as an instrument that would allow pilots to fly indefinitely through the clouds, implying that without it they could not.
It was hardly a secret. Already by the end of World War I, thinkers on both sides of the Atlantic had understood the difficulties of the banked turn, but the great majority of professional pilots con
tinued to disdain the idea of any crutch. A group of Sperry’s employees split off and, calling themselves the Pioneer Instrument Company, went into production with the device. They found the market difficult. For the next twenty years customers kept complaining to them about a mysterious problem: The instruments worked just fine in clear air, but as soon as they were taken into clouds they began to indicate turns.
Not all pilots were that stupid. One of the first cloud flights with this new device, the turn indicator, was made in 1918 by William Ocker, an Army captain and an experienced aviator. Though Ocker, too, lost control and spiraled out of the overcast, he assumed that the error was his, and he set off on an eleven-year quest for good answers.
During the 1920s a few of the more progressive airmail pilots, operating under deadly pressure to push the weather, began to admit the need to control their bank angles by reference to the instruments. Charles Lindbergh was one of those converts. When he crossed the Atlantic in 1927, he used a turn indicator with which he had first experimented only months before, and he readily admitted afterward that it had kept him from spiraling into the sea. His description of that historic piece of instrument flying holds true today:
What lies outside doesn’t matter. My world and my life are compressed within these fabric walls. Flying blind is difficult enough in smooth air. In this swirling cloud, it calls for all the concentration I can muster. The turn and bank indicators, the air speed, the altimeter, and the compass, all those phosphorescent lines and dots in front of me, must be kept in proper place. When a single one strays off, the rest go chasing after it like so many sheep, and have to be caught quickly and carefully herded back into position again.