THE FANTASY FIGHTER

Diving inverted toward the desert floor 10,000 feet below, the numbers on your digital altimeter shrinking at a terrific rate, you notice the G meter pop to life as you roll out of the dive and ease the stick back: 5.6 . . . 6.2 . . . 7.5. . . .

Then, all at once, as the plane reaches level flight, the Gs slide off, the airspeed holds at .9 Mach and the altimeter numbers stop flashing at 150 feet.

Beyond the canopy, you see you are booming along at nearly the speed of sound, searing the tops of the trees, drumming the desert with a scorching twin-engine roar and hurtling like a cannonball toward the Chocolate Mountains swimming on the horizon.

And, absolutely wreathed in an immense adrenal grin, you realize that this is without doubt the most fun you can have while sitting still.

If your idea of video thrills is a heart-stopping round of Nintendo, it is probably a good thing you can’t get your hands on the Marines’ new F/A-18 Delta flight simulator.

It is the ultimate video game, an on-the-ground re-creation of the flight of one of the most breathtaking fighter planes ever produced, and it makes every hot-ticket ride you ever stood in line for seem like an evening in the Barcalounger watching “Wheel of Fortune.”

Barely three months old, it is designed to allow fighter pilots to learn the basics of the newest two-seat version of the F/A-18, popularly known as the Hornet, without expending a drop of fuel.

The new simulator arrived at the Marine Corps Air Station at El Toro about the same time the first new F/A-18 Delta fighters showed up there. El Toro is the first Marine base in the country to take delivery of the new night fighter, which is designed to replace the base’s two squadrons of aging A-6/E Intruder fighters. Eventually, all Intruders in the Marine Corps will be replaced by the new Hornets, and El Toro will receive 38 of them.

Every aircraft flown by the Navy and Marine Corps has a corresponding flight simulator to help in the initial training and continuing education of pilots and radar officers.

However, where other simulators have been limited in their ability to reproduce actual flying situations, the new F/A-18 Delta simulator is almost frighteningly realistic.

Want to do a little dogfighting with an F-15? Easy. Want to throw in a MIG “Flogger” and maybe a couple of SAM missiles? A cinch. Want to make it interesting and do all that hassling at low altitude between the buildings in downtown Los Angeles? No sweat. Punch a few buttons and bingo--you’re buzzing Dodger Stadium at 1.3 Mach.

“When I walked into the simulator for the first time, I was blown away by the visuals,” said 1st Lt. Bob Underwood, 28, an F/A-18 pilot with the VMFA-323 squadron--known as the Death Rattlers--at El Toro. “I’d never seen visuals in any simulator before, and the Delta’s visuals are awesome. It’ll water your eyes how realistic they are. I thought I was in ‘Star Wars’ and I was a Jedi knight or something.”

Indeed, Luke Skywalker would feel right at home, except for one thing: The simulator doesn’t move. Not an inch, ever. But try telling that to anyone climbing into it and firing it up for the first time.

It works like this: The guts of the simulator is an exact duplicate of the cockpit of the F/A-18 Delta that rests on top of a kind of high pedestal. It is surrounded, quite literally, by what technicians call a dome but what is actually a huge spherical movie screen.

During a flight in the simulator, computer-generated images, called visuals, are projected from three lenses onto every inch of the dome. The result is an accurate three-dimensional reproduction of the California or Arizona desert, the San Diego coast, the El Toro-Laguna Hills area or any other location in the American southwest over which Marine pilots might fly.

While the visuals are obviously not real life, they do represent reality. The computer programs that generate the projected images are made up of data from actual topographical maps.

This means that if a pilot using a Southern California desert program sees hills on the horizon in the simulator, or a two-lane highway below, the hills and the highway are not just for show, but are really out there in the desert.

“We have most of the major landmarks,” said James Leach, a technician who operates a large console in an adjacent room that controls, among other things, which program the pilots will see. “Most of the major highways are where they’re supposed to be too.”

To Underwood--whose call sign is “Face”--it all “looks like a really well-done cartoon. You know it’s fake, but it looks pretty real.”

The clincher: The visuals respond with pinpoint accuracy to absolutely anything the pilot does. A quick move to the left with the stick will cause the horizon to spin. Pull back and the horizon falls away and eventually reappears from above.

Every action is reflected in the cockpit instruments, most obviously on the heads-up display (HUD), a series of critical readouts that appear directly in front of the pilot’s eyes on a small pane of glass, allowing him to keep his eyes on his surroundings and on his instruments simultaneously.

The speed with which the visuals move correlates exactly to what would happen in real life: throttle up and they pass faster; descend to a lower level and they go by faster still. Lose control and they may spin wildly.

And try--just try-- not to move your body sympathetically when an aileron roll wheels the landscape around 360 degrees. And try not to lean back and forth as you rocket through mountain passes at low level, snapping over into hard bank after hard bank.

All this digitized derring-do, however, doesn’t come cheaply. The new simulator cost $20 million. A new F/A-18 Delta costs $20.9 million.

Still, to the pilots and their instructors, it is worth every penny.

“The biggest thing is emergencies,” Underwood said. “The F-18 is a great airplane. It’s well-built and it never breaks. I’ve only had a couple of emergencies since I’ve been flying. And you can get lulled into a sense of security in the Hornet because of that. But you get in the simulator, and they’ll throw everything at you, engine fires and all kinds of things. Multiple emergencies too. Just everything that can happen.”

Simulating emergencies in actual flight, Underwood said, would mean shooting dice with airmen’s lives, not to mention millions of dollars worth of high-performance, high-explosive aircraft. The simulator fills in the gap.

“You don’t realize it,” he said, “but when you have an actual emergency in the airplane you don’t have to think about what you’re doing. Your mind just goes right back to when you were in the simulator. You’ve already been in that situation in the simulator, and it was a pretty stressful, intense environment because you were in the training command. It takes a lot of the fear factor away.”

Each new Hornet pilot makes 10 flights, or “hops,” in the simulator before ever climbing into an actual plane in order to become familiar with the aircraft’s performance characteristics and its dizzying array of digital instruments, Underwood said.

“It makes you comfortable and you know where everything is,” he said. “It’s a pretty radical change coming to the F-18 from, say, the A-4 like I did. The A-4 has the needle instruments all over the place. But in an F-18 everything’s digital. You have to retrain your thinking to digital.”

And, said Underwood, the F-18 has an on-board computer that automatically trims the plane to level flight to compensate for any acceleration or deceleration, a task that is left to the pilot in the A-4. The simulator helped him adapt.

The simulator saves money as well as time. Pilots preparing to fly a combat exercise in which they will fire missiles can practice doing that in the simulator (smoke trails from the missiles are visible on the dome). Technicians in the control room also can punch in different kinds of weather, different locations (including an aircraft carrier), can fire surface-to-air missiles at the simulator pilot, and can even fly against the pilot, controlling a computer-generated enemy plane with a stick and throttle mounted in front of a monitor in the control room.

And, when the technicians throw an emergency into the program, the pilots become familiar with the female voice--known universally to pilots as “Bitching Betty”--that announces the problem automatically into their headsets.

The technicians say the pilots love the simulator and put in an hour or two in it each month. But, Underwood said, they also take their time under the dome seriously.

“As a student,” he said, “the way you’re trained in the Navy and Marines is if you crash that simulator in a training environment, then you’ve flunked a flight, and it’s a big deal. They go into why you crashed it, and you could actually flunk out. A ‘down’ is what they call it in training command. You get three of those and you’re out of the program, and you can get all three in the simulator.

“You sweat in there. You’re flying and you don’t want to crash. If you do, you feel like you just killed yourself.”

Leach put it into a dauntingly simple equation: “If they can’t do it in here, they can’t do it in the airplane.”

Still, Underwood said, the simulator, complete as it is, is no substitute for flying.

“Everything looks the same, and I’m pulling the same tactics and skills I would be if I were in the airplane,” Underwood said. “But you can’t feel the G. It doesn’t give you the feeling of motion. Dealing with the G and being able to do things while you’re under the G is a big part of the game plan. For instance, I never flew a plane with afterburner before. It kicks in and accelerates with the Gs and, no matter how fast you’re going, it’s pretty awesome. Nothing can take the place of a pilot actually going out there and flying.”

And, he added, there is one ultimate difference.

“In the simulator,” he said, “you know you’re not going to die no matter what you do, even if you crash it. But in the airplane, if you crash it, you know you’re going to die.”

There is, however, a world of fun to be had in the simulator if your flying career isn’t necessarily on the line. When the simulator is unoccupied for a few minutes--a rarity--the technicians occasionally take a turn at the controls (Leach punched up a program for the Miramar-San Diego area and promptly flew under the Coronado Island Bridge). And, Underwood said, the simulator has proven to be a useful recruiting and public relations tool.

“I take a lot of fathers and sons in there if the sons are interested in being pilots,” he said, “and the sons usually do really well because they might be used to playing computer games. They’re great for the hand-eye coordination.

“I’ve taken a lot of different people in there and every one of them is like a little kid when they get into it. They’re just blown away. They call me the next day and say, ‘Man, I had dreams all last night about flying the F-18.’ I’ve heard of grown men, 40 years old, calling their dads and telling them what they did in the simulator.”