The catwalk was scarcely eighteen inches wide, hemmed in on both sides by racks of electronic control units, circuit breaker chassis, and bundles of orange test wiring. The noise here was deafening—a continuous, roaring vacuum sound as eighty thousand pounds of thrust tore through the slipstream two feet beyond the thin aluminum skin of the fuselage. Covington didn't waste time talking. He lunged forward, swinging the heavy pipe wrench in a brutal, horizontal arc aimed straight at my collarbone. In the tight confines of the avionics bay, there was no room to duck or dodge. I stepped directly into his swing, closing the distance before the heavy steel head could gather maximum velocity. The shaft of the wrench struck my left forearm with bone-jarring force, the shock radiating straight through my elbow into my shoulder, but my forward momentum drove my right shoulder deep into his sternum.
We slammed back against the main flight control computer rack. The impact jarred the steel housing, sending a cascade of diagnostic lights on the chassis from steady green to flashing amber. Covington grunted, his breath catching in his throat, and brought his knee up hard toward my groin. I twisted my hips, taking the blow across the heavy muscle of my outer thigh, and drove the palm of my right hand upward against the hard plastic bridge of his respirator. The straps snapped with a sharp ping. The mask tore away from his face, hanging uselessly by one elastic cord around his neck. The raw, chemical stench of the compartment hit him instantly. He choked, his eyes tearing up, his fingers clawing desperately at his throat as the concentrated malathion vapor caught his airway.
He swung the wrench again, blind and clumsy, but I caught his wrist with both hands, driving his arm backward against the sharp steel edge of an avionics mounting tray. The wrench slipped from his fingers, clattering through the catwalk grating and dropping into the black void of the forward cargo hold twenty feet below. Before he could regain his footing, I hooked my left leg behind his ankle and drove my weight downward. He hit the steel grating on his back, the breath driven out of him in a loud, wheezing gasp. I drove my right knee hard into his chest, pinning his left shoulder against the rack, and grabbed the heavy zip-ties from David’s hand through the opening above.
"David!" I yelled over the roar of the hull. "Get down here and grab his legs!" David dropped through the blowout opening with none of the hesitation he had shown in the galley. He landed across Covington's shins, driving his knees into the mechanic's ankles, while I pulled Covington’s right arm behind his back, wrenched his left wrist to meet it, and pulled the industrial plastic tie until the teeth locked with a harsh, ratcheting zip. I pulled a second tie around his elbows, cinching it until his shoulders were locked together. Covington thrashed against the grating, his face purple, foam flecking his lips as he struggled to inhale the tainted air of the bay. "The... the bypass..." he choked out, his eyes bulging as he glared up at me. "You can't undo it... the code locks the bus... you cut it, the elevator locks down..."
I ignored him, lunging past his writhing shoulders toward the brass air manifold. The valve handle was secured with three wraps of stainless safety wire. I grabbed the wire with my bare fingers, ignoring the sharp edges slicing into my skin, and twisted the braided strand until it snapped. With a single violent shove, I threw the brass lever back ninety degrees to port. The metallic hiss of escaping pesticide ceased. The spring-loaded flapper valve slammed shut inside the duct with a heavy clunk, sealing the cockpit loop and reopening the galley line to the passenger deck scrubbers. "Where is the maintenance binder?" I demanded, leaning down until my face was three inches from his ear. "The Queens avionics jumper schematic. Where did you put it?"
Covington glared at me through bloodshot eyes, spitting a mouthful of bloody saliva onto the floor grating. "Find it yourself... bitch. You have four minutes... four minutes before the hull crosses ten thousand... then the depressurization switch dumps the cabin air anyway." I reached into the side pocket of his unzipped canvas tool bag resting on the lower equipment rack. My fingers hit a cold, rigid plastic binder: the 777-300ER SYSTEM INTEGRATION MANUAL: DIGITAL DATA BUS OVERRIDE & AVIONICS BREAKOUT. Tucked inside the front cover was a folded engineering diagram drawn on white grid paper, marked with yellow highlighter across the secondary flight data recorder junction.
CHAPTER 8
Covington hadn't just tapped into the flight computer; he had used an analog bridging resistor to trick the digital bus into reading an electrical runaway fault. If the flight computer thought a control servo was running wild, it yielded authority to the secondary maintenance bus—which he had slaved to the black box under the throttle quadrant. To kill his override without freezing the control surfaces, I didn't need to cut the wires. I just had to pull the master data reference fuse on the rear bulkhead of the flight deck, forcing the fly-by-wire system to drop into direct secondary mechanical law. "David," I yelled, grabbing the manual and Covington’s canvas belt. "Help me heave him through the hatch. We don't leave him down here near the cable runs."