He reached into a pocket of his immersion suit and removed a rubber suction cap. He fixed it to the lamp, and pressed the other side against the outer hull. He jiggled the lamp, but it remained fixed. The pool of light fell upon the grey metal shell.
He loosened the final screw, pocketed it, and lifted the carapace away. Inside it were the carbon fibre braces to withstand pressure at depth. Beneath the carapace were a number of further box-like housings with neoprene seals. He half turned a spring-loaded catch, then lifted the first of the inner covers. What he saw, as he had suspected from the diagram but which still surprised and daunted him, resembled a dug-out, exposed telephone junction box he had once seen beneath the sidewalk of Pennsylvania Avenue in Washington. The telephone engineers had exposed a mass of bright, spiderish wiring, incomprehensible, baffling. He shook his head, and began to learn the nature of what he looked at, remembering Quin's voice guiding him through the wiring diagrams and the "Leopard" manual. Printed circuit boards, a sickly grey-white and green where the copper was coated with anti-corrosion varnish; on the boards, resistors with bright bands of colour in the lamplight, capacitors in tubes of various sizes, some sheathed in coloured plastic, some like sucked cough lozenges. He nodded to himself. His eyes recognised the number of small boxes set out as regularly and rigidly as units of some eighteenth-century army drawn up for battle. Pins like defences protruded from the boxes, glinting gold. Microprocessors.
It was no longer mysterious. Merely a collection of components. He breathed easily, with satisfaction. He was now the telephone engineer, not the passer-by. The sheer mass of wiring, however, prevented complacency; all colour coded, lashed into ropes with fine cords. Each circuit board had a serial number, which he would read to Quin or Quin would instruct him to test, and each component, however tiny it might be, fitted in its place in company with a reference number.
His finger traced across the bulk of large power transformers, mounted on blocks of metal and used to dissipate heat from the system. Then his eye began to register the miniature switches, labelled Self-Test Facility and the multi-pin sockets labelled Input Tester Socket Type 27 P3D. They were his heart of the matter, all he really needed to recognise.
He hefted the carapace away from him, together with the inner cover, and placed them gingerly in the pressure hull beyond his packs, steadying them until he considered neither of them would slip into the chasm. Then he removed his special test kit from the pack, and clipped it to his belt. A bead of wetness ran down his cheek, then dropped from his jaw. It would take hours, just the checking. The thought made his hands almost nerveless and caused a cramp in his arched back and neck.
"Okay," he said in a whisper.
Quin was back almost immediately, the eagerness evident in his voice. "Begin with the Opto-Electric Converter," he said. "You can identify that?"
Clark studied the exposed boards. "Yes, got it."
"Good. Switch SW One off, and SW Two on."
"Right."
" Rotate SW One to Test."
"Yes."
"Look at the two rows of LEDs — describe the sequence of lights to me."
Clark watched the two rows of light emitting diodes. The top row lit up one by one, accompanied by a low hum. As the last one illuminated, the first light of the lower row lit up, followed by its companions, the top row of lights going out immediately. When the second row was complete it, too, went out, and the first light of the top row lit up once more, repeating the sequence.
When Clark had reached the end of the sequence in his description, Quin interrupted him.
"Switch off. Everything's working properly there. The transducers, the wiring, the fibre-optics and the connectors are all working as they should."
"Uh," Clark grunted, disappointed in a childish, impatient way. Nothing wrong. He sighed.
The Nimrod banked sharply to starboard. Eastoe was trying to come round on to the northern leg, across Varangerhalvoya, and two of the MiG-23s had crossed the nose of the aircraft as soon as he began to change course. Aubrey gripped the sides of his seat fiercely, but he did not allow any expression to appear on his face. He could hear the Russian flight leader, speaking in correct, unemotional English, demanding that Eastoe continue on his former course, west along the Norwegian coast towards North Cape. Eastoe remained silent.
The Nimrod, however declared his intention. It dipped violently as the two MiGs banked up and away, flicking with the agility of flies across the darkness, illuminated by a flash of lightning only when they were already more than a mile away, and beginning a turn to bring them back alongside the Nimrod. Eastoe levelled the big aircraft below the flight level of the Russian interceptors.
"Everyone all right — you, Mr Aubrey?"
"Thank you, yes. No more than unsettled." The console in front of Aubrey crackled, and what might have been a voice tried unsuccessfully to communicate something to them. Quin had turned up the volume to maximum, and was leaning forward.
"What did you say, Clark? Clark, I can't hear you."
"What's the matter?" Aubrey snapped fearfully. "What's happening?" Quin shook his head and shrugged. "Eastoe — we can't hear Clark."
"I'm at the limit, Mr Aubrey. Over a hundred miles out. I'm sorry, but I'm trying to shave the corner off the northbound leg. You'll have to bear with me." There was no satisfaction in the voice. Eastoe had suspended his personal feud with Aubrey.
"Very well." The storm filled the empty ether that was being amplified by the console. A MiG popped into Aubrey's vision, below and almost beneath the port wing of the Nimrod. It had bobbed there like a cork tossed on rough water. There was only the one. Aubrey bent his head and stared through the starboard window opposite him. He could see two more of the Russian interceptors. They were close in, as if juggling for position in order to refuel from the Nimrod. Dangerously close.
Drawn to what he suspected was happening, Aubrey left his seat and crossed to the starboard side of the Nimrod. The aircraft was sliding into a turn, banking slightly and nose-down so that the metal floop had tilted like the floor of some disorientating fairground tunnel. The closest MiG was edging into the Nimrod like a smaller animal ingratiating himself. Its speed had matched the Nimrod's and Aubrey could already see the helmeted head of the pilot within the bubble of the canopy. The flying was skilful even as it was threatening and dangerous. The Nimrod was being headed off, a sheep being directed by a sheepdog. A collision appeared inevitable as their paths converged. Aubrey could do nothing except watch with an appalled fascination. His old frail body trembled with its sense of mortality.
He dimly heard the Nimrod's four Spey engines increase their power, and he felt the nose tilt upwards suddenly. He hung on to a bracket like a straphanger in a tube train, his. body wanting to lurch towards the tail of the aircraft. The MiG-23 appeared, then, whisked away from the window, like a fly that had been swatted. Even as the Nimrod climbed it began to bank to starboard, pushing Aubrey against the fuselage and his face into the double window port. He felt the glass against his cheek, and his arm aching from its hold on the bracket. The MiG was below them, the other Russian interceptor above, at a distance that implied respect or nerves. Aubrey felt himself hanging over the chasm of thirty thousand feet, imagined the rocks and the landscape below them.
He heard Clark's voice bellow behind him, reporting a stage of his inspection. Then two hands moved his small, frail body, and he was able to let go his hold on the bracket. He looked round into the face of the young flight-lieutenant who was in charge of communications.