Jerry turned as far around as he could, nodding at his first officer. “Yeah, you, too, Dan. Be damned careful down there.”
“I will.”
Dan looked back at the copilot’s seat where Josh Begich was punching his way through electrical diagrams. Carol was back in the cockpit, waiting to kneel as best she could in the cramped space behind the captain’s seat to be the relay for Dan. He could see the strain on her face as she struggled to smile at him.
Frank Erlichman was anxiously waiting for Dan at the bottom of the ladder.
“Any progress, Frank?”
The man nodded, his words precise and spoken in a slow meter in pace with the seriousness of the situation. “I have been tracing wires as fast as I could, and I believe I know where the main controls have been spliced; although whoever wired this modification did such a professional job you would never know it wasn’t a part of the original wiring harness.”
“Show me, please,” Dan replied, following the man to the right side rack. “We don’t have much time.”
“Ja, I think,” Frank continued, “…if we cut here and here… ready to reconnect as before… and then splice these wires with these… we might be able to reroute control of the autoflight system. But… it is a big gamble.”
“How much?”
“Pardon?”
“How much is guesswork and how much is certain, Frank?”
The man looked the copilot in the eye without a trace of humor and laughed ruefully. “It is all guesswork. I am not certain of anything.”
“Okay. Is there a safer approach?”
“Yes. I think so. Those racks in what you call the cabinet?”
“Yes?”
“It is full of relays. Why would it be full of relays if the purpose wasn’t to shunt power and control?”
Dan looked at the long rows of small, square metal cubes and a semi-ancient memory popped into his head, a memory of trying to explain what a relay was to his mother, who thought it somehow would explain what her son was doing to make money in the software business.
“Think of it this way, Mom,” he’d said. “All the lights in town have gone off in a storm. Now the storm is gone, and I want to turn all the lights on again. But that’s a huge amount of electricity, and I want to just flick a little switch. So, instead of routing a river of power through tiny wires that would burn up, I use a relay. I flick a switch, a little power goes through a little wire and powers an electromagnet, the electromagnet causes a metal rod to move a much bigger switch from “off” to “on,” and I never have to get close to that much bigger and more dangerous amount of electricity.”
It had been a noble attempt, but when she explained to friends that Dan controlled the city’s light system, he gave up.
Frank, he realized, was talking, and he’d let himself drift.
“In other words,” Frank repeated, “…I think that is how it is done. My thinking is that the relays are not normally powered on, so that when they’re not powered, all is normal. When something causes them to come on and do their job of switching, that’s when everything changes. The flight controls, for instance. The relay is energized, one of them cuts the power going to and from your flight controls… your sidestick controls on the flight deck… removing your manual input to the autoflight computers. Instead, it sends false information to the same autoflight computers, enabling them to be commanded perhaps by radio from outside, or by some internal program. In any event, as long as those relays are active, you can’t interfere.”
“Like someone just unplugged our cockpit controls and plugged in an alternate set of controls.”
“Exactly.”
“And we’re just along for the ride. Okay, I’m with you.”
“Well…” Frank continued, “…my theory is that if we interrupt the power that’s letting those relays disconnect your cockpit, they’ll shift to the off position and let go of the various controls.”
“Great!”
Frank Erlichman was shaking his head energetically. “But wait, please. I have to warn you that if we’re wrong… if we shut down the wrong one… even turning it back on might not cause it to latch again. Without a wiring diagram—”
“I understand, Frank. But we have to try. So we just selectively and physically pull the relays out of their respective sockets and see what happens?”
“No, no, no! If we pull a relay, it will depower that relay, yes, but it will also break whatever circuits are flowing through it when the relay is not powered on.”
“Oh, Lord, of course. When the thing is off, the normal power to, for instance, the sidestick controllers, flow through that very relay.”
“Yes. We need to depower each relay without pulling it out of the socket.”
“So how do we do that? We can’t get to the back of this cabinet where all those wires come in.”
“I’m sorry… I don’t see a way without finding the power leads and cutting them.”
Dan leaned against the starboard electrical rack for few seconds, letting his mind race over the options. He was missing something, and it was pissing him off.
All available resources…
The phrase echoed through his conscious mind like a rebuke, and he raised an index finger in a wait gesture.
“Stay here. Don’t pull anything. I’ll be right back.”
Scrambling up and down the small ladder through the narrow hatchway to the cockpit was getting easier, or he was becoming less aware of the bruises. Carol saw him climbing out and was just regaining her feet when he emerged, taking her by the shoulders to move her aside gently on the way to the right side of the cockpit.
“Josh…?”
The boy’s head snapped around toward him as he flashed a wait gesture to Jerry who was looking puzzled. Bill Breem was looking at him as well, but saying nothing.
“Okay. Help me figure this out, if you can. Both of you.” Dan described the cube-shaped electrical relays and the inability to reach the power leads behind them. Breem began asking questions, and he and Dan were firing ideas back and forth too intently to notice Josh Begich trying to snag their attention. Frustrated, the boy reached up and grabbed Dan’s left forearm.
“You guys are missing it.”
“Missing what?” Breem asked, not unkindly.
“If a relay is powered on one side and the other side is holding open the circuit you want to close, pulling that relay out of its socket for a few seconds or even minutes will do no harm. You can pull the relay, pop the cover off, cut the power leads, then put it back in and the little switch inside will no longer be powered, the little plunger rod inside will be spring-loaded back, and the circuit it was designed to interrupt will no longer be interrupted, it will be restored.”
Dan looked at Bill Breem who was nodding.
“He is absolutely right.”
Dan turned back to Josh. “Okay, but what if we get the wrong one and want to repower it? If we’ve cut the power leads inside…”
“Well, the relays I’m used to working with have little prongs on the back going into the socket. Just bend the power prongs aside, and if you need to repower it, bend them back and plug it back in.”
“Josh, you just earned your keep! Thank you. That’s what I was missing.”
Dan whirled around to return to the electronics bay as Jerry caught his arm.
“I’ve slowed us down considerably, Dan, and I think we’ve got at least two hours before we’re over Tel Aviv now. At least it looks like we’re still bore sighted.”
“Got it. Pray hard, buddy. I’m going to start pulling things.”
Within five minutes Dan had put on the insulating coat and gloves he’d used before and with Frank briefed and standing beside him with a pair of needle nosed pliers, he reached in gingerly and grasped the first cube, pulling it smoothly from its socket.