“We can’t call Boston Center to change their flight plans,” Lafferty said, “unless they declare an air defense emergency. We’ll have to send them VFR, without a flight plan.”
“Then do it,” Cole said. “Give them the computer sequence point, and have them keep in touch by HF radio or SATCOM. We’re going to need a weather briefing for the OCCULT EAGLE orbit area. If the weather goes to shit, we’ll have to lie to the FAA that World War Three has just started. Until then, get those four Thunder planes into the orbit area any way you can.”
TWENTY-TWO
Soon it was just Furness and Kelly in the air refueling track. Zero-Five and Zero-Six were going to be delayed several more minutes, so Furness and Kelly hit the tanker one more time before the tanker had to depart, and they exited the air refueling track and headed over to the Montpelier radio navigation station, requested and received a safe altitude block, and set up an orbit pattern to wait.
Furness checked to see what Fogelman was up to, now that things had calmed down enough for them to take a breather and get caught up. He had the nav data page on the left MFD and the nav present position page on the right MFD. He stayed in the radarscope a long time, nudging the radar tracking handle onto a radar return and softly muttering to himself. When she checked the FIXMAG readout on the left Multi-Function Display, it read 12600 FT — over a two-nautical-mile difference between where the system thought it was and where Fogelman was trying to tell it where it was. “How’s your system looking, Mark?” Rebecca asked.
“Shitty,” he replied.
“You got a big buffer load in there,” she offered, referring to the large FIXMAG reading. “What are you trying a fix on — the Brookfield overpass?” The radar fixpoints near the Montpelier radio navigation station were well known to all Plattsburgh crewmembers, and the overpass was a good one to use — very easy to identify and aim on. But there were two overpasses that crossed the highway twenty miles south of the capital city of Vermont — and they were exactly two miles apart. If he was on the wrong one, and the system was good, that would be a reason why FIXMAG read twelve thousand feet. If he was on the right one, that meant that the inertial navigation system was off by two miles — bad enough so that it might be better to just start over and reinitialize. “Make sure you got the right overpass.”
“I got the right one, pilot,” Fogelman snapped. “Stop harping on me.” He moved the PRES POS CORR switch to IN, jiggled the tracking handle a few more times to refine his crosshair placement — Rebecca noted that he didn’t try to select another offset aimpoint to check his crosshair placement, which would have told him if he was on the right aimpoint or not — then hit the ENT FIX option-select switch on the left MFD.
On Rebecca’s right MFD, a message flashed on the screen about twenty seconds later that read PP REAS FAIL. The INS had rejected the fix because of the disparity between where it thought it was and where Fogelman decided it was. The INS itself thought it was navigating accurately. In three years of flying the RF-111G with its two INS systems, and especially after the GPS satellite navigation system was installed, Furness had never seen a fix rejected by the system that wasn’t due to operator error. “I think you picked the wrong—”
“The thing has gone to shit,” Fogelman complained. “I’ll jam this fix in, and if it spits it out I’ll reinitialize.”
“But don’t you think—”
But Fogelman wasn’t going to wait. He selected RDR PP on his right MFD to change the fix method, then entered OVR WHL — he was going to “jam” the fix, or tell the INS to accept his crosshair placement as perfect no matter what. He refined his crosshairs once again and took the fix.
Kiss that INS good-bye, Furness thought. An OVR WHL fix, or Override Wholevalue, updated the system present position but did not update the system velocities. Now the INS present position was off by at least two miles, and the INS velocities, which were obviously bad before the fix, were just as bad now and probably getting worse. She had never seen anyone take an override fix except in the simulator, mainly because the INS was always very good. Expect that puppy to roll over any minute now, she thought grimly. On the left Multi-Function Display, she saw that Fogelman had just about every possible sensor selected — both INS units, Doppler, TAS (True Air Speed computer), and GPS satellite navigation. The velocities from these sensors would all feed into INS number one through the computers, and eventually INS one would discover that it was out to lunch — then it would “kill” itself, or take itself off-line. That would happen in about …
“Thunder Zero-One, this is control, how do you hear?”
Furness keyed her mike. “Loud and clear. Go ahead.”
“Thunder Zero-One …” There were a few seconds of hesitation; then: “Thunder Zero-One and Zero-Four, we need you to fly to and hold at destination number two-eight-nine, repeat, two-eight-nine. You will cancel IFR, squawk standby, and proceed to that destination. You will be given additional instructions later via AFSATCOM. Attempt to contact Thunder Zero-Two and Zero-Three on the command post or RBS frequencies and direct them to join you at destination two-eight-nine.” AFSATCOM, or Air Force Satellite Communications System, was a secure global communications network that transmitted coded messages via satellite from the Pentagon, Air Combat Command headquarters in Virginia, Strategic Command Headquarters in Nebraska, or any combat-unit command post, directly to tactical aircraft. In the 1980s when the FB-111A was pulling nuclear alert, AFSATCOM was the primary method that aircrews received their dreaded “go-to-war” messages. When the Strategic Air Command was stood down and the FB-111 became the F-111G in the new Air Combat Command, AFSATCOM was no longer used. The system still worked and crews still trained with it, but lately it was used to pass routine bombing-range scores and maintenance messages from the planes to the local command posts.
Without waiting on Fogelman, Furness called up the destination number on the left Multi-Function Display and checked its coordinates on her chart. The RF-111G Digital Computer Complex held 350 sets of coordinates, called data points or destinations, which could be a turnpoint, target, or radar offset aimpoint. Most local training missions used only the first two hundred data points; the other data points were never used except for unusual training missions, such as long cross-country flights, RED FLAG exercises in Nevada, or special test flights.
To her surprise, the coordinates weren’t on her map, and she had to pull out a standard civil aeronautical chart to find the spot — it was several hundred miles east, about a hundred miles out over the Atlantic Ocean, at an ADIZ entry point called FREEZ. Many times the RF-111G aircraft ran maritime strike and reconnaissance missions out over the ocean or Lake Ontario to practice overwater photo procedures or AGM-84 Harpoon antiship-missile strike procedures. The checkpoint they mentioned was in the middle of a large overwater warning area between Kennebunkport and Brunswick, Maine. When reentering U.S. airspace, aircraft had to enter at a specific spot at the proper time for positive identification purposes or else fighter-interceptors could be scrambled to visually identify the “intruder.”