Glide Path

by Arthur C. Clarke

  “It’s a funny thing,” he said to Hatton, “but the Americans just can’t draw circuit diagrams. I’ve never seen such a mess as these.”

  The biologist, who could barely cope with a crystal set, had no strong views on the subject, but he suspected that Alan’s condemnation was a little unfair.

  “They were probably so busy making the gear that they had no time to draw pretty pictures. Anyway, why are you so keen on it? You’ve done nothing else for the last three days.”

  Alan carefully inked in another line before answering.

  “It’s the only way to learn how a new piece of equipment works,” he answered. “Besides, if I’ve got to train RAF mechs to run it, I must make sure I’m one jump ahead of them.”

  That was not the only answer, though it was a good one. Alan’s aesthetic sense was rudimentary, but he derived considerable artistic pleasure from a well-laid-out circuit diagram. The problem was that of arranging, on a single sheet of paper, the symbols for several hundred resistors, capacitors, and electron tubes—and then showing all the connecting wires in such a way that the functioning of the circuit was made perfectly clear. One of the rules of the game was that there should be the minimum number of points where wires crossed each other; another was that the wiring should be of the least possible length. The two goals were not always compatible.

  Until Alan had completed his notes, he was having as little as possible to do with the Mark I; in any case, at this stage, he would only be in the way. He had paid a single visit to the guarded hangar housing the gear, and had departed both shaken and impressed.

  As usual, it had been raining when Deveraux and Hatton had driven him out to the hangar in T6, the Ford truck that was the unit’s chief means of transportation. The vehicle had arrived from the United States with the GCD team, but did not seem to have any legal owner. Probably it still belonged to the Massachusetts Institute of Technology, and probably MIT was still looking for it.

  When they had presented their passes to the armed guard, they had been allowed into the great metal cavern, lit inadequately by a few naked light bulbs thirty feet above the ground, which threw isolated pools of radiance on the oil-stained concrete. In one of these pools were standing two large, black-painted vehicles.

  The smaller truck was about the size and shape of a furniture removal van, and was in no way unusual apart from the stubby aircraft-type aerials jutting from its roof. Alan did not give it a second glance; he was too busy staring at the larger vehicle, which was quite the oddest thing he had ever seen on wheels.

  From the forward end of the roof, just above the driver’s cab, sprouted a large cylinder, proportioned like one of the stovepipe hats beloved by the Victorians. From the other end reared a rectangular structure—a long, thin box stretching all the way from the ground to a point at least fifteen feet in the air. In addition to this, one side of the truck bulged out into a plywood-covered bay window. Presumably all these excrescences concealed radar scanners, but from their shape they must be unlike any that Alan had ever encountered before.

  “That’s the transmitter truck,” explained Hatton. “It holds our mobile power plant—a big diesel-electric set—and the antennas that produce our radar beams. It’s nothing but a radar station on wheels, and there’s no room inside it for any operators. They’re here in the control van; this is where the actual talking down is done. When it’s done,” he added gloomily.

  He pulled open the door, drew aside a heavily weighted blackout curtain, and waved Alan into the van. Almost the whole interior was occupied by a massive rack of electronic gear, stretching from floor to ceiling. There were no fewer than four radar screens, as well as a prominent vertical panel carrying three large meters. One was labeled ELEVATION, another AZIMUTH, the third RANGE. It needed no great intelligence to deduce that this was where the controller sat, and that these meters told him what was happening to the aircraft he was talking down.

  One of the display units lay on the controller’s desk, its wiring scattered around it in a tangled maze as Dr. Wendt performed some surgical operation upon it. The prevailing smell, however, was not that of ether and antiseptics, but of soldering irons, burned insulation, and tobacco smoke. There was something peculiarly dead and depressing, Alan had always thought, about any large radar set when the power was switched off, and he had never received that impression as strongly as now. The needles of the meters all lay supine against their zero stops; no lights were gleaming, either in red warning or green reassurance, on the banked racks and panels. The display screens themselves were like blind windows, looking onto nothingness—until Dr. Wendt could give them vision again.

  Alexander Wendt was the oldest member of the team; he had reached the ripe age of thirty-three, and his companions never let him forget it. He was a striking figure, thanks to his magnificent spade beard and the slender cigarette holder he usually carried clenched between his teeth. This, Alan soon discovered, served as a kind of emotional semaphore whose angle accurately signaled all its owner’s moods, from despondency to elation.

  Sprawling full-length under the controller’s bench were Pat Connor and Howard Rawlings III. (“What does the III stand for?” Alan had asked. “It means that he was one of triplets, but they drowned the other two,” was Pat’s explanation.) Howard was prodding hopefully around with the probes of a test meter, calling out the readings while Pat checked them against figures in a notebook. They were too busy to look up when the visitors all but walked over their prostrate bodies.

  “Where’s Benny?” asked Hatton.

  Wendt nodded vaguely toward the door.

  “Over in the transmitter truck. He’s trying to run the X-band maggie up to twenty-five Kv.”

  Hatton pressed a key on the controller’s desk and spoke into a microphone.

  “How’s it going, Benny?” he asked.

  There was a brief pause. Then a loud-speaker somewhere in the massed banks of electronic equipment made a short announcement. No knowledge of Yiddish whatsoever was necessary to deduce that the X-band maggie had not run up to twenty-five Kv.

  “I’ll go over and give him a hand,” said Deveraux. “He sounds a bit browned off.”

  “Thanks, Dev,” remarked Pat’s voice from the floor. “I always wondered what a typically British understatement was like. That’ll do very nicely until a better one comes along.”

  As they retreated from the battlefield—stepping carefully over the recumbent bodies—Hatton asked Alan, with a mixture of pride and exasperation, “Well, what do you think of it?”

  “It looks an awful lot of equipment just to land an aircraft.”

  Hatton, who normally walked with a slight stoop, reared up in annoyance. Like Deveraux, with whom he had a great deal in common, he was impatient of silly remarks, and he had heard this one so many times that it was beginning to rankle.

  “I know a case,” he said, controlling himself with an obvious effort, “where a Bomber Command squadron lost three Lanes and four Stirlings on a single op, because fog closed in before they could get home. If they’d had GCD, it would have paid for itself in one night.”

  Suitably abashed, Alan quickly changed the subject.

  “When are we going to see Professor Schuster?” he asked. “I’m anxious to meet him.”

  “He’s still on a scrounging-cum-propaganda tour,” answered Hatton. “No one knows when he’ll be back—and at the moment no one is at all anxious to see him.”

  Alan was quite shocked by this.

  “Why,” he said, “I thought he was very popular.”

  Hatton cracked a rather glacial smile.

  “We’re all very fond of him,” he answered. “But you don’t know the Professor. As a theoretician he’s superb; as a practical man…”

  He gave an eloquent shrug of his shoulders and pointed back at the hangar.

  “We can consider ourselves lucky that he’s not in there helping the boys. If he was, they’d never get the Mark I working again.”

  Ala
n’s naive remarks had an unexpected sequel a few days later, when Hatton suddenly announced: “Better pack your toothbrush and spare socks; we’re going away for a couple of days.”

  “Where?” asked Alan, reasonably enough. Hatton often made mysterious trips away from the station, as befitted a King Boffin, but this was the first time he had invited anyone to go with him.

  “There’s a spot of trouble at a Bomber Command station, and it’s time you saw some Ops. Until you do, you won’t understand what all this is about.”

  Alan never did discover exactly what the “spot of trouble” was, even after Hatton had whipped him right across England by train and special car; apparently it concerned some long-range navigational aid that was misbehaving. For as soon as they arrived at the airfield, the scientist handed him over to the Senior Flying Control Officer, who appeared to be an old friend.

  “Here he is,” he said ambiguously, leaving Alan wondering what build-up he had received. “Park him in a corner of the tower where he won’t be in the way. I’ll collect him when I’m through.” Alan was given a chair, a small desk, a mug of tea, a generous supply of official documents—and left to his own devices.

  Around him, as evening fell, the airfield came to life. Out of the darkness, from the dispersals where they had already been fueled and bombed-up, the Lancasters were revving their engines. Thousands of horsepower—perhaps more power than any army in history had ever mustered before this age—was concentrated within these few square miles, waiting to be unleashed. What the target was, only a few men knew; that was the secret upon which the lives of all these crews, and the success of their mission, depended. Security was so strict that, for hours before the operation, the station had been virtually sealed off from the outside world.

  And now the control tower was crackling with messages and orders as the squadrons were set rolling along the perimeter track. An intricate machine—as intricate as any that man had ever built—was being set in motion. It comprised hundreds of aircraft, scattered over many bases; vast communications networks and radar chains; Air-Sea Rescue boats already setting out into the dark waters of the North Sea; agents far inside enemy territory; and, in the very center of it, the pilots and navigators, engineers and gunners, who flew mission after mission despite the odds mounting inexorably against them.

  One by one A Able, B Baker, C Charlie, and their companions acknowledged the flashing Aldis light from the control tower and went roaring down the runway to face the known and unknown hazards that lay ahead. Only Y Yoke failed to join that eastward-flowing stream of destruction; some mechanical failure developed at the last moment, and it had to taxi off into a dispersal site. Alan felt very sorry for the crew; it must be a terrible anticlimax, after you had steeled yourself for a mission, for it to be aborted. It was true that the grounding might have saved your life, but you could never prove it, and would always feel that you had let the squadron down.

  The sky ceased to reverberate; the last red glow from incandescent exhaust faded among the stars. The English countryside turned to sleep, but in a few hours some German town would wake to nightmare.

  There would be no sleep, however, for anyone in the control tower. Now that the raid was under way, the waiting had begun. The tension seemed to focus on a single loudspeaker, high on the wall above the Senior Controller’s desk. No sound came from it except a faint crackling, but, if all went well, at some undisclosed hour it would call a few words which would mean nothing except to a few men at the Air Ministry. It would tell them that the squadron was over the target; or that it was under heavy attack, or that it had turned back—or many other things.

  Time passed. Cups of coffee circulated; so did little jokes and reminiscences, but no one seemed to be taking any notice of them Alan had never intended to stay this long, and miss a night’s sleep, but now he found it impossible to leave.

  It was after 2:00 A.M. when the loudspeaker woke to life. “The hounds of spring,” it announced, “are on winter’s traces.” That was all; the words were clear and unhurried, as if spoken into a telephone in some peaceful office. Even the background of engine noise was quite subdued; there was no trace of the concussions that Alan had half expected to hear.

  Whether it was a message of triumph or disaster, there was no way of telling. It certainly sounded reassuring—but even that might be a blind.

  Half an hour later, the speaker gave the unexpected news that the price of Spam had gone up by sixpence a pound. This did not sound quite so good, but there was little point in worrying about it. However, the messages did allow Alan to deduce one piece of information. Assuming that the return journey would be quicker than the outward one, the bombers should be back just before dawn.

  Across one wall of the control tower was a large blackboard, divided into rows and columns. The columns read A Able, B Baker, C Charlie, D Dove, and most of the way through the alphabet, with the name of the pilot against each aircraft. There were also columns for call signs, frequencies, and other information, and a final column for notes—blank except for the disgraced Y Yoke.

  As the small hours became steadily larger, eyes could be seen straying more and more frequently toward this silent reminder. The tension, which had slackened off after those radio messages, began to grow again. Wireless operators sat hunched over their dials, making minute adjustments from time to time; the Flying Control Officer seemed on the brink of making phone calls, but kept changing his mind; the WAAF clerks had dropped their knitting and their magazines. Everyone was waiting.

  At 6:30 A.M., a telephone rang. The FCO grabbed it, listened for a minute, then turned to his assistant.

  “F Freddie—he’s landed at Hornchurch. Starboard outer feathered, but otherwise OK.”

  The information was chalked up on the board, and thereafter things began to happen quickly. Over telephone and radio, news of the returning squadron flowed in. Twenty minutes later, the thunder of the first approaching engines disturbed the dawn.

  S Sugar was first to touch down, and the blanks on the blackboard started to fill up. It was like watching a jigsaw puzzle being completed; by 7:15 most of the pieces had been fitted back into place; two like F Freddie were absent but accounted for, and three were missing.

  This, thought Alan, as he watched the dawn of a lovely winter day, must be the worst part of the whole job. P Peter, T Tommy, and X X-Ray might still be on their way home, staggering along on two or three engines, and might need all the help they could get. On the other hand, their troubles might have ended hours ago.

  By the time hunger and fatigue sent Alan to breakfast, T Tommy had been rubbed off the board. The returning aircrews had seen it spiral down over the target; some parachutes had emerged, they could not say how many. But of P Peter and X X-Ray, there was still no news when Alan and Hatton left the station. There never would be, now.

  6

  We’re growing,” said Deveraux to Alan, as they left the Officers’ Mess after breakfast. “The Adj tells me that three WAAF operators and one radar mech arrived last night. He’s just discovered that they belong to us.”

  “I hope we’ve got some work for them,” said Alan. “What rank is the mech?”

  “Sergeant—R double-A F. Probably a bit Bolshie, like most Australians. I don’t think I’ve ever seen one salute an officer.”

  He said this without any particular rancor; as long as an airman was efficient and kept out of trouble, that was all that mattered. Deveraux himself was efficient—highly so—but he had not always succeeded in keeping out of trouble. This time, though, Group could hardly turn down that overdue promotion—if GCD lived up to its claims and he could train the RAF to use it…

  When they arrived at “D” Flight, the newcomers were waiting for them in the cramped office that served as HQ. The WAAFs were capable-looking girls, ranging in appearance from homely to passable; the Sergeant was a tough little bantam of a man in the dark-blue uniform of the Royal Australian Air Force.

  He saluted smartly, thus refuti
ng Deveraux.

  “Nice to see you again, sir,” he said to Alan. “Remember me?” That “sir” was the first and very nearly the last that he ever received from Sgt. McGregor.

  Alan did a swift double take. During his term as an instructor, several hundred airmen had passed through his classes. They had been from all parts of the world—Britain, Canada, South Africa, Australia, France, Poland—and though at one time he had known the names of every one of them, most of them had faded from memory after the farewell party that terminated each course.

  But it did not take him long to place the Sergeant; even as a humble aircraftsman II, McGregor had not been a very forgettable person. Like Alan, he had been that rare phenomenon—a radar mech who actually knew something about radio when he entered the service. Indeed, he was an amateur with his own license, operating a short-wave station somewhere in the Australian outback.

  Alan was genuinely pleased to meet one of his old pupils, and to find that he had gone up in the world despite his tuition.

  “It seems a long time ago since we had that passing-out party in the NAAFI,” he said. “I hope the sheep farm’s still managing without you. And why haven’t you got your commission yet? You were always talking about it.”

  “Station, not farm,” corrected McGregor with a grimace of disapproval. “And as for the commission, I’ve changed my mind. Above sergeant you have too many responsibilities; below it, not enough privilege. So I’ll stick here, if that’s all right with everyone.”

  Similar thoughts had often passed through Alan’s mind, but he was intelligent enough to reject them—as, he was sure, did McGregor. The balance between responsibility and privilege could be struck at any level, if one had the ability to function at that level. Alan had met miserable Aircraftsmen II—and suspected that there might even be happy air chief marshals.