Glide Path

by Arthur C. Clarke

  “Certainly, certainly,” said the CO.

  Alan was speechless, completely taken off guard. His mind whirled in all directions like a crazy compass needle, trying to think of reasons why he could not possibly, conceivably accept Dennis’s kind offer—for that it was Collins’s idea he had no doubt. The obvious reply—that he had to stay to supervise the equipment—Dennis could demolish in a moment. Sergeant McGregor and Corporal Hart between them knew at least as much about the Mark I as did Alan.

  He might think of other excuses, even plausible ones, which the Station Commander would accept. But this was no longer a matter of logic or even common sense. It was a private affair, between Dennis and himself—an inescapable challenge to his own pride and self-respect. Well, he had been hankering for such a challenge; now it had come.

  And suddenly, with a flash of insight, he knew exactly what had led to this. He should never have told Lucille, with such obvious relish, the story of Flight Lieutenant Collins’s crash landing in the dung heap. It had been a cheap victory—until this presentation of the final bill.

  “I’m ready,” he said. “Will someone get me a chute?”

  25

  The runway was a road to nowhere, fading into the mist a few hundred feet beyond the Perspex windows. On a night like this, thought Alan, one needed radar not merely to land, but to take off. As long as he lived he would remember this moment, with the Anson quivering eagerly on the wet concrete, the roar of its motors merging with the roar of the flames, as they carved their narrow zone of visibility through the fog. As long as he lived…

  Precisely. Even now, while they were still taxiing slowly to the center of the runway, there was time to call the whole thing off. But he knew that this was so impossible that it was not worth a second thought. There was no question of bravery—only the fear of being marked down as a coward for the rest of his career. How many heroes, he wondered, had in reality been driven by this same impulse? There could be no such thing as an act of pure, unadulterated bravery when the world was watching.

  He wondered if Dennis was as unconcerned and self-assured as he appeared to be. Of course, he had plenty to occupy him; the pure mechanics of taking off in these conditions, and then following his radioed instructions, would keep him from worrying too much about what happened next. It was Alan who had merely to observe—and to think.

  The roar of the engines deepened as the aircraft started to move down the fire-girt valley through the fog. The gentle pressure of acceleration thrust Alan back into his seat, and he felt the floor tilt beneath him as the tail lifted from the ground. Faster, faster the Anson rushed through the burning night (did Dennis know how much runway was left?) until the sudden change in the quality of the vibration told Alan what he could not otherwise have known. They were airborne, lifting up into the sodden, light-less sky.

  And in that moment, as they left the ground and the undercarriage began whining up into the fuselage, Alan’s fears fell away with the earth beneath. There was no going back now; he was committed.

  It was easy to understand how, in the days before blind-flying instruments were invented, pilots in fog had become hopelessly confused and had even flown upside down. There was no real sensation of motion; they were sitting in a dimly lit, resonating void that had no contact with any other world. The Perspex windows might not have been there for all the help they gave; all that could be seen through them was the fitful glare of the exhausts, and the more distant twinkle of the navigation lights on the wing-tips. Sometimes even these were lost as the aircraft plunged into a thicker stratum of fog.

  Yet another world did exist; if they were not aware of it, it was conscious of them. The calm and omniscient voice over the VHF radio sounded in Alan’s ears.

  “Longstop calling C Charlie. I have you in view. Continue course on three two zero and climb to three thousand feet.”

  “Wilco,” Dennis answered. Then he switched over to the intercom. “How are you feeling?” he asked his passenger, in a friendly voice.

  “Fine,” replied Alan, mildly astonished to realize that this was perfectly true. Now that he was airborne, apprehension had given way to an unmistakable zest; he was actually glad to be up here, on this filthy night, proving his confidence in the system more un-arguably than could be done in a hundred years of fair-weather flying.

  The rate-of-climb indicator dropped back to zero as the aircraft leveled out at three thousand feet. Only a few seconds later came the next order from the Traffic Director, turning them ninety degrees to the left. Alan guessed that the Controller wanted to bring them around the sky and on to the approach with as little waste of time as possible. He heartily approved of his, though the fact that every three minutes saved would reduce the cost of feeding FIDO by a thousand pounds did not even enter his calculations.

  The steady roar of the Cheetah engines, drawing them on through the trackless night, was wonderfully reassuring. There was something safe and dependable about an Anson, even if it was no beauty and seemed to be composed mostly of straight lines and flat surfaces. It would still be plodding through the sky years after the Spitfire, with its lovely, sweeping curves, had passed into history.

  Course 050—the last lap before they were vectored on to the approach. They had gone right around the sky, tracing out three sides of a huge square, and would soon be making a final right-angle turn as they headed in to the runway. It was a little peculiar, come to think of it, that if you subtracted ninety from 050 you got 320; compass bearings seemed simple enough except when you had to work them out in your head. No wonder that pilots under stress made foolish mistakes that sent them flying off on a reciprocal, in exactly the opposite direction to the one they really wanted.

  No such errors could happen here; too many people were monitoring the performance. Yet it was with a considerable sense of relief that Alan heard a new voice say: “Approach Controller here. I have you at six miles.” The first part of the task was over, and they were safely inside the narrow field of view of the precision system, heading in toward the runway.

  He remembered the first time he had flown on an approach. Well, there was no hope now of watching the runway magically aligning itself with the nose of the aircraft from three or four miles away. They would probably not even see the runway until they were over it—or until they felt the bump and knew that they were on the ground. Yet though he realized how foolish it was, he could not stop himself from pressing against the clammy Perspex, half hoping that he could already see some sign of the double walls of fire that would guide them through the fog. But the sense of sight was now utterly useless; their only link with the ground was that quietly confident voice over the radio.

  “Four and a half miles to go,” said the Controller. “Maintain present course and start to reduce height at fife hundred feet a minute.”

  The vibration of the aircraft slackened as the motors were throttled back, and the Anson began to fall down the gentle slope that, in just three minutes’ time, should bring them over the end of the runway. Everything was going according to plan—the virtual absence of cross wind made it almost too easy—yet there was a mounting tension in the pit of Alan’s stomach. He wished that, like Dennis, he had something to occupy his mind as the ground came steadily, invisibly closer. All the obstacles around the airfield became suddenly exaggerated in his imagination; it seemed that trees and hangars and radio masts and power lines were rearing up to scrape them from the sky…

  What was Dennis thinking? He stole a glance at his companion, but that placid, too-handsome profile betrayed absolutely no trace of emotion. To Flight Lieutenant Collins, DFC, this was just another routine piece of bus driving. Such calm confidence was reassuring, yet at the same time Alan found it vaguely irritating.

  “Three miles to go. You are getting a little high. Increase rate of descent.”

  All one’s natural instincts revolted at the thought of descending even more swiftly than before into this swirling chaos. It was easy for the Controller to giv
e the order, as he watched his elevation needle climb above the glide path; Alan had seen him do it a hundred times. He had never realized how much confidence was required on the part of the pilot to obey this order without hesitation.

  “Two miles to go. Check wheels down.”

  On the usual training approaches, that order was given but not acted upon, because the aircraft would be overshooting without attempting to land. Dennis must by now have made more approaches with his undercarriage up than with it down, which was a bad habit to acquire. Even the best pilots sometimes forgot this important trifle, despite the automatic warnings that were supposed to bring it to their attention.

  “You are a little to the left of the runway. Change course three degrees right; I say again, three degrees right. One and a half miles to go.”

  Three degrees was the smallest correction that could reasonably be given; it was a final nudge to get the aircraft exactly lined up. Alan had a comforting mental picture of the azimuth-error needle creeping slowly back to its central zero position as they came precisely on course.

  From now on, things would happen quickly; every second would count. Only one mile to go—they must be less than five hundred feet above the runway. In half a minute they would be upon it, descending into that sea of fire like a moth into a candle flame. And still there was no vestige of light from the all-encompassing darkness.

  “Three quarters of a mile to go. You are on the glide path. Continue present rate of descent. Half a mile to go.” (Was even the Controller’s calm, bedside manner beginning to sound a trifle strained?) “A quarter of a mile to go. The runway is a little to your left; I say again, the runway is a little to your left—go ahead and land.”

  And now, unmistakably, there was a lifting of the darkness ahead. An ill-defined glow, like the first hint of dawn, had appeared where until a moment before had been nothing but the blackest night. It warmed Alan’s heart to see it; they were nearly home. He glanced once again at his companion, wondering how he was reacting. Dennis was hunched over the wheel, straining his eyes toward that waxing but still-formless light. There was a trace of anxiety in his stare—but that, surely, was natural enough during these last critical moments.

  The first line of fire appeared so suddenly that it took them by surprise, even though they had been expecting it. Marching into the mist both behind and ahead of them, it lay at an acute angle to their course—and that was absurd, for they should have been flying straight along it. Something had gone badly wrong; the aircraft’s heading was wildly in error, and the runway was certainly not “a little to your left” as the Controller had said.

  Dennis was struggling to get C Charlie back over the runway, but it was too late. The error had been so unexpected, so completely unreasonable, that he had no time to correct it. One by one the four lines of fire slid by beneath them; then they had crabbed across the runway and were once more out in the darkness.

  As Dennis pulled back the wheel to gain altitude, he reached for his mike and called the truck.

  “C Charlie to Longstop. Something wrong with your line-up. The runway was on our right, not left. Please check. Over.”

  There was a brief silence. Then an abashed voice replied:

  “Longstop calling C Charlie. Message received and understood. Am investigating. Continue on course three two zero and change to Channel D. Out.”

  Dennis switched radio channels, then spoke to Alan over the intercom.

  “That was a bloody poor effort. Wonder what went wrong?”

  Alan could think of many explanations—too many for his peace of mind. But he would never have thought of the right one.

  26

  There was no particular reason why Squadron Leader Strickland should have driven out to watch the show, but a Security Officer never had to justify his curiosity. He had gone no more than half a mile before he was very sorry to have left his office.

  For he was lost, on his own airfield. It was impossible to see through the streaming windshield, and he was forced to use the edge of the perimeter track as his guide. But something had gone wrong (he had been a bit suspicious about that sharp turn to the left a few yards back), and he was afraid he had veered off onto one of the aircraft-dispersal sites.

  He was sure of it when he almost ran into the parked Liberator. It was impossible to drive ahead, and he could not see to reverse. But he knew exactly where he was now—the runway was only a couple of hundred yards ahead—and it would be quite safe to take a short cut over the grass. Even in the heaviest rain, this side of the airfield never got bogged.

  He had covered a careful fifty feet when there was a sudden “twang,” followed almost at once by a metallic crash as something hanged into the car. “What the hell!” exclaimed the Squadron Leader, and reluctantly climbed out into the rain to inspect the damage.

  It was very slight. He had hooked a steel guy wire, almost invisible in the rain, and pulled down the object it was supporting. Lying under his front wheel was a crumpled pyramid of yellow-painted tin, attached to a six-foot iron pole.

  Squadron Leader Strickland looked at it with considerable annoyance. People shouldn’t leave such obstacles standing around the airfield, he told himself. He dismissed that childish thought as soon as it materialized; no one did put up contraptions like this except for very good reasons.

  He inspected the thing more closely and then, with some discomfort, realized what it was. Though he was not a technical man, he was familiar with all the airfield equipment, and he knew that this was something to do with GCD. It was also very near the runway in operation; that meant they might be using it now…

  The Security Officer groaned. He couldn’t take chances, and he’d have to get a message through to the GCD truck somehow. That meant finding his way back to the perimeter track, and then locating the nearest telephone to Flying Control. With the best of luck, that would take at least ten minutes.

  It took more like twenty, for the guy wire was tangled around his front axle, and by the time he had unwound it his temper was as filthy as his uniform. He had barely finished when he heard the roar of approaching engines; when C Charlie overshot the airfield and climbed away into the night, he felt vague premonitions of guilt. They were fully justified.

  ***

  Before C Charlie had passed over the truck, the postmortem was in progress. Somewhat rudely pushing the azimuth operator aside, Corporal Hart examined the glowing images on the display tube with the utmost care. He had done the lining up himself, only ten minutes ago, and had checked it again immediately before the approach.

  Runway 320 was somewhat tricky, but did not present any real problems. The touchdown point was just over the brow of a hill, and this meant that it was impossible to place a radar reflector on the center line of the runway itself; it would have been hidden from view. The lining up depended, therefore, on a corner reflector placed at a carefully measured distance to the right of the runway, but in sight of the truck.

  Well, there it was, where it should be. No—just a minute—something was wrong! Corporal Hart stared at the pattern of glowing blobs and lines, which he had scrutinized so many times; and suddenly he realized that the most important part was missing.

  That big, juicy echo on which he had carefully aligned the entire GCD system was not their reflector; it was at least a hundred feet off to the right. He guessed that it was a parked aircraft; nothing else in that area could give such a large radar echo. By lining up on that, instead of on the proper reflector, he had skewed the whole approach path across the sky.

  He felt cold with fright. What would Mr. Bishop say when he heard about it? He might get court-martialed—it was pure luck that C Charlie hadn’t crashed on that last approach…

  But it wasn’t his fault, he told himself. If the reflector had been there, everything would have been OK. Who would have dreamed that it was missing? Some of their earlier reflectors had been blown down, but nowadays they were all set in concrete and properly guyed. It must be sabotage…
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br />   “Well, Hart,” called the Approach Controller impatiently, “what’s the trouble?”

  Corporal Hart broke the news as gently as he could.

  “Our marker’s missing, sir. Someone’s knocked it down or taken it away. That means we can’t check our lineup.”

  “But I thought we were supposed to be lined up!”

  Hart gulped.

  “I’m afraid we used the wrong echo, because we didn’t know our own marker was missing. That’s why the glide path was so badly off.”

  “Then do something about it, quickly. They’re in the circuit—they’ll be making another approach in five minutes.”

  Do what? thought Hart helplessly. In this filthy weather it would take at least half an hour to get another reflector, locate the right position, and fix it in place.

  In an emergency, even the dullest minds are capable of surprising feats, and Corporal Hart was certainly not dull; indeed, he was almost as smart as he thought he was. His hesitation lasted only for a few seconds; then he switched on the intercom to the transmitter truck.

  “Mac,” he called urgently, “we’ve lost our offset marker and can’t line up the system. Is LAC Jackson there?”

  “Yes, but what can he do about it?”

  Jackson was an athletic young Canadian who had a passion for physical fitness and was much better than average at almost any sport one cared to mention. The WAAFs thought the world of him, and he had done a good deal to fill the vacuum left by Pat Connor.

  “Ask him to grab a bike and head for the runway. When he gets there, tell him to cycle to touchdown just as fast as he can, keeping exactly in the middle of the runway. He must get clear as soon as he reaches the perimeter track, unless he wants C Charlie to land on top of him. Make sure he understands.”