She went on, looking through the Structure Reports, the Interior Cabin Reports, the relevant PMA records for the counterfeit slats locking pin and the counterfeit thruster cowl. Steadily, patiently, she worked on into the night

It was after ten o'clock when she again turned to the faults printout from Flight 545. She had been hoping she could skip this, and use the flight recorder data instead. But now there was nothing to do but slog through it.

Yawning, tired, she stared at the columns of numbers on the first page:

A/S PWR TEST 00000010000

AIL SERVO COMP 00001001000

AOA INV 10200010001

CFDS SENS FAIL 00000010000

CRZ CMD MON INV 10000020100

EL SERVO COMP 00000000010

EPR/N1 TRA-1 00000010000

FMS SPEED INV 00000040000

.PRESS ALT INV 00000030000

G/S SPEED ANG 00000010000

SLAT XSIT T/O 00000000000

G/S DEV INV 00100050001

GND SPD INV 00000021000

TAS INV 00001010000

TAT INV 00000010000

AUX 1 00000000000

AUX 2 00000000000

AUX 3 00000000000

AUX COA 01000000000

A/S ROX-P 00000010000

RDR PROX-1 00001001000

AOA BTA 10200000001

FDS RG 00000010000

F-CMD MON 10000020100

She didn't want to do this. She hadn't eaten dinner yet, and she knew she should eat. Anyway, the only questions she had about these fault listings were the AUX readings. She had asked Ron, and he had said the first was the auxiliary power unit, the second and third were unused, and the fourth, AUX COA, was a customer installed line. But there wasn't anything on those lines, Ron said, because a zero reading was normal. It was the default reading.

So she was really finished with this listing.

She was done.

Casey stood up at her desk, stretched, looked at her watch. It was ten-fifteen. She'd better get some sleep, she thought. After all, she was going to appear on television tomorrow. She didn't want her mother to call afterward saying, "Dear, you looked so tired…."

Casey folded up the printout, and put it away.

Zero, she thought, was the perfect default value. Because that was what she was coming up with, on this particular night's work.

A big zero.

Nothing.

"A big fat zero," she said aloud. "Means nothing on the line."

She didn't want to think what it meant-that time was running out, that her plan to push the investigation had failed, and that she was going to end up in front of a television camera tomorrow afternoon, with the famous Marty Reardon asking her questions, and she would have no good answers to give him. Except the answers that John Marder wanted her to give.

Just lie. Hell with it.

Maybe that was how it was going to turn out.

You 're old enough to know how it works.

Casey turned out her desk light, and started for the door.

She said good night to Esther, the cleaning woman, and went out into the hallway. She got into the elevator, and pushed the button to go down to the ground floor.

The button lit up when she touched it.

Glowing"1"

She yawned as the doors started to close. She was really very tired. It was silly to work this late. She'd make foolish mistakes, overlook things.

She looked at the glowing button.

And then it hit her.

"Forget something?" Esther said, as Casey came back into the office.

"No," Casey said.

She rifled through the sheets on her desk. Fast, searching. Tossing papers in all directions. Letting them flutter to the floor.

Ron had said the default was zero, and therefore when you got a zero you didn't know if the line was used or not. But if there was a 1… then that would mean… She found the listing, ran her finger down the columns of numbers:

AUX 1 00000000000

AUX 2 00000000000

AUX 3 00000000000

AUX COA 01000000000

There was a numeral 1! AUX COA had registered a fault, on the second leg of the flight That meant the AUX COA line was being used by the aircraft.

But what was it used for?

She sucked in her breath.

She hardly dared to hope.

Ron said that AUX COA was a line for Customer Optional Additions. The customer used it for add-ons, like a QAR.

The QAR was the Quick Access Recorder, another flight data recorder installed to help the maintenance crews. It recorded many of the same parameters as a regular DFDR. If a QAR was on this aircraft, it could solve all her problems.

But Ron insisted this plane didn't have a QAR.

He said he'd looked in the tail, which was where it was usually installed on an N-22. And it wasn't there.

Had he ever looked anywhere else?

Had he really searched the plane?

Because Casey knew an optional item like the QAR was not subject to FAA regulation. It could be anyplace in the aircraft the operator wanted it-in the aft accessory compartment, or the cargo hold, or the radio rack beneath the cockpit… It could be just about anywhere.

Had Ron really looked?

She decided to check for herself.

She spent the next ten minutes thumbing through thick Service Repair Manuals for the N-22, without any success. The manuals didn't mention the QAR at all, or at least she couldn't find any reference. But the manuals she kept in her office were her personal copies; Casey wasn't directly involved in maintenance, and she didn't have the latest versions. Most of the manuals dated back to her own arrival at the company; they were five years old.

That was when she noticed the Heads-Up Display, sitting on her desk.

Wait a minute, she thought. She grabbed the goggles, slipped them on. She plugged them into the CD player. She pressed the power switch.

Nothing happened.

She fiddled with the equipment for a few moments, until she realized there was no CD-ROM in the machine. She looked in the cardboard box, found a silver platter, and slid it into the player. She pressed the power button again.

The goggles glowed. She was staring at a page from the first maintenance manual, projected onto the inside of the goggles. She wasn't quite sure how the system worked, because the goggles were just an inch from her eyes, but the projected page appeared to float in space, two feet in front of

her. The page was almost transparent; she could see right through it.

Korman liked to say that virtual reality was virtually useless, except for a few specialized applications. One was maintenance. Busy people working in technical environments, people who had their hands full, or covered in grease, didn't have the time or inclination to look through a thick manual. If you were thirty feet up in the air trying to repair a jet engine, you couldn't carry a stack of five-pound manuals around with you. So virtual displays were perfect for those situations… And Korman had built one.

By pressing buttons on the CD player, Casey found that she could scroll through the manuals. There was also a search function, that flashed up a keyboard hanging in space; she had to repeatedly press another button to move a pointer to the letter Q, then A, then R. It was clumsy.

But it worked.

After a moment of whirring, a page hung in the air before her:

N-22

QUICK ACCESS RECORDER (QAR)

RECOMMENDED LOCATIONS

Pressing more buttons, she scrolled through a sequence of diagrams, showing in detail all the places where the QAR could be located on the N-22 aircraft.

There were about thirty places in all.

Casey clipped the player onto her belt, and headed for the door.