The Finger in the Sky Affair - Leslie Peter - Страница 14
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"Okay, okay, the Royal Air Force," Solo interrupted with a smile. "We do know that one."
"Roger and out!...Sorry, chaps. As I say, they worked out a system for the V-bombers, which of course had to be able to fly in any weather. And the bombers duly used it. But unfortunately it wasn't good enough for the civil airlines."
"Good grief, why not?"
"Margins of error, old boy. The R.A.F.'s prepared to accept a very small calculated risk—any operational war force must be, obviously. The particular figure determining things in this case was one fatality in one hundred thousand landings where the system was in full use."
"And this small percentage of calculated error was not good enough for civil planes?" Illya asked.
"Not by a long chalk. The Air Registration Board wouldn't certify full use of any equipment until it had proved a safety standard of one fatality per ten million landings...Nevertheless B.E.A. started using Smith's equipment on their Tridents in 1964. This controlled the aircraft's height until the moment of touchdown. Then B.O.A.C. equipped V.C. 10's with similar gear developed by Elliott-Bendix."
"Was this used on all landings?"
"No. Mainly for fog. A limited use in fact. They were waiting for the International Civil Aviation Organization to give the final go ahead on world-wide adoption of the system in principle."
"And the principle is?"
"Plances carry the equipment in a square box housed in the cockpit. As they approach the airport, the box fixes them on a localizer beam which brings them in line with the runway to be used for the landing. Then another ground transmitter broadcasts an electronic beam down which the plane rides, as it were, to establish the correct glide path."
"And the gear in the box causes the plane's controls to adjust themselves so as to maintain the correct altitude and inclination for touchdown?"
"Dead on target, old chap. Hole in one. The pilot still has to control the sideways aspect, the roll of his wings, himself—but the height's always the most difficult part of it, after all. And even in good weather this limited use of the stuff increases the safety factor no end."
"Aren't they developing an—er—extension to the system so that the roll factor will be taken care of too?"
"They are. Have, in fact. Supposed to be installed later this year. In the meantime, our own gear—the Murchison-Spears, you know—already takes care of this."
"Is it based on the same principles?" Illya asked.
The Technical Director struck a match and sucked the flame noisily into the sodden bowl of his pipe. "Partly," he replied. "Fact is, the gear that fixes the plane on the localizer beam is a dead crib—so far as that's possible within the copyright infringement laws. But the part that adjusts the height and inclination is quite different. Instead of relying on a ground-to-air electronic beam and riding down it, the Murchison-Spears equipment works on a system more like ordinary radar."
"You mean it emits a signal and deduces information from the way that signal is echoed back—then causes the aircraft to act upon this?"
"Broadly speaking, yes. Murchison designed the altitude-and-aspect end of it—that's simple in theory but extremely sophisticated in design. And Spears—he's the hydraulics wizard—handled the part that deals with the roll factor. Basically, this is just a sensitizer at each wing-tip and something very like the old-fashioned balance-pipe between them. But again—the means he used to achieve this are electronically most advanced. The sensitizers—which both transmit and receive pulses, after all—are extraordinarily compact and ingenious."
"How do you yourself account for the three T.C.A. crashes here?"
The man with the pipe lit another match. For some moments he puffed away behind his private smokescreenm, then he rose to his feet and crossed the room to the window. "Very difficult question to answer," he said at last, with his back to them. "Mind, I haven't had time to go over the bits—the actual pieces of wreckage of the latest one. They're being assembled on the floor in a hangar nearby, as nearly as possible in their original relationship to one another. And that's a hell of a job when you've got perhaps several tens of thousands of segments—buckled, torn, melted, twisted, distorted and what-not."
"I can imagine."
"Nevertheless, my chaps and I have formed certain opinions—and they are only opinions, based on interpretation of the information supplied by other bods, and not deductions from data observed by ourselves. That'll come later."
"Any opinion, any suggestion, any hint will be valuable, sir."
"Yes. Well—for what it's worth, all my chaps underwrite what the accident investigation johnnies said: that there was no human error in any of the three prangs. And that there was nothing wrong with any of the planes. Or with their normal controls, for that matter."
"You're saying, in effect, that there was something wrong with the Murchison-Spears equipment?"
"No, old boy. That's exactly what I'm not saying. I'm saying there was nothing wrong with anything else. You can draw what deductions you want to from that. In view of the fact that the M-S gear was proved to be in perfect condition after each crash, I simply cannot say that, ergo, it must have been the gear that was at fault. Until our own investigations have been completed, I must say nothing: my mind must remain open..."
"If the gear had been at fault, what would you say—unofficially, of course—would have been the—er—likeliest thing to have happened to it? That could have left it in perfect condition afterwards, that is."
"Seems obvious to me, old chap. In such a case—if one existed!—one would have to look for a set of conditions causing false readings on the equipment. Something that caused the box to direct the aircraft as though the ground wasn't where it really was...if you get my meaning!"
"You mean the box could have acted as though the runway was higher or lower than it really is, for example?"
"I mean," the Director said carefully, "I'd be inclined to look for a situation in which such a thing could happen."
"And if such a set of conditions existed—which part of the gear would you be inclined to suspect of being affected?"
"Look—the box divides itself pretty definitely into three separate complexes, doesn't it? The bit getting it in line with the runway to start with...and after that the altitude-and-aspect gear, and finally the wing-tip equipment that controls the roll. Right?"
"We're with you."
"Right. Now it would seem unlikely that the first is in any way affected: all three crashes actually occurred on the runway, so the planes must have been accurately lined up, eh?...And again, no eyewitnesses have mentioned anything like a sideslip or a wingtip digging in or anything of that sort. Admittedly the last one did cartwheel—but that was apparently only after the under-carriage had been wrecked on the first impact. So it seems—shall we say?—unlikely that the wingtip gubbins caused the crashes."
"Which leaves the altitude and glide-angle equipment?"
"Exactly. You examine all the witnesses' statements. Seventy per cent of 'em say something like 'the plane seemed to fly straight into the ground'. And the survivor of the last one was trying to say something to the nurse in the ambulance. Unfortunately, she didn't speak English—but we gather he was spouting something about height, or too high, or something. All of which seems to me to suggest either wrong altimeter readings or wrong glide angles."
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