When the fighter pilots at Miramar Naval Air Station in San Diego hear the sound, they snap to full alert. Click. Radar operators close their eyes and just listen, knowing precisely what is coming their way. Click. Click.

High heels in the hallway. Softer than a sonic boom, less penetrating than an F-14 afterburner, the footsteps of 6′ Christine Fox, 30, nevertheless carry the impact of a preemptive strike. “They always know when I’m coming,” she says with a sigh, “because I’m one of the few people around here whose heels click.”

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To Navy aviators—described by one of their own as “chauvinistic, macho, self-centered, overzealous, close-minded, hardheaded, egotistical and highly capable”—the sight of Fox striding through headquarters is as enjoyable as a scared MiG pilot running for home.

Well, almost.

She makes her living developing tactics for the defense of aircraft carriers, and she is about to be immortalized—or at least fictionalized. Paramount Pictures is currently filming Top Gun, a drama about the Navy’s most advanced jet-fighter weapons school, which is located at Miramar. Tom Cruise plays a hot pilot, and Kelly McGillis plays the tall, beautiful civilian who lectures him and other fighter pilots on enemy aircraft, which is a reasonable approximation of what Fox really does.

Fox is a civilian employee of the Center for Naval Analyses (CNA), a Navy think tank. In 1983 she was dispatched to the West Coast to serve on the staff of the admiral who commands airborne early-warning and fighter aircraft for the U.S. Pacific fleet. Says Capt. Monroe Smith, until recently the operations officer for the wing: “She’s the smartest woman I’ve ever met. I like women for a lot of things and being smart isn’t usually one of them.” Fox is currently the only woman working in the field for CNA.

All of this sounds impressive, but it still translates into a government job. Fox shares an office about as spacious as a wardroom on a WWII submarine. She has a government-issue metal desk and an orange vinyl armchair so grimy most visitors prefer to stand. Over her desk is a list of the differences between an ape and a fighter pilot. You’d be surprised how many there are. Number 19: “You can tell something to an ape.” Number 26: “It doesn’t take a million dollars to train an ape.”

Across the road from her office is TOPGUN, officially designated the U.S. Navy Fighter Weapons School but called TOPGUN by just about everybody on the base. Established to fight an ominous trend that surfaced during the Vietnam War—a decline in the combat effectiveness of Navy fighter pilots—TOPGUN has become a highly coveted assignment.

Unlike the McGillis character in the movie, Fox seldom works closely with TOPGUN students. She is a specialist in Maritime Air Superiority (MAS), the establishment and aggressive air defense of an imaginary perimeter around an aircraft-carrier battle group. How far that perimeter extends is classified, as is much of what she does. “My actual job has much more to do with the guy in the back seat of the plane, the radar-intercept operator, than the guy in the front, the pilot. I don’t know anything about flying airplanes, but I know a lot about the guy in the back seat—his mission, his radar and his missiles.”

In the film, Cruise is “Maverick”—that’s his nickname or “call sign.” Navy aviators really do use such nicknames among themselves to encourage trust and familiarity, since rank doesn’t count for much during air combat. Captain Smith answers to “Hawk,” although junior officers usually show respect by addressing him as “Captain Hawk.” It was Smith who gave Fox her distinctive call sign—”Legs.”

When Top Gun producers Don Simpson and Jerry Bruckheimer were trying to decide on a proper love interest for the film, they first considered groupies and gymnasts as paramours for Cruise. (McGillis says she was cast as a gymnast in the first script she received and wasn’t interested.) During a meeting with the producers, the admiral commanding the wing asked Fox to step into his office and a part was born.

McGillis now plays an astrophysicist named “Charlie” who lectures TOPGUN students on enemy fighter capabilities. This is where the movie begins peeling off from reality. Also, Fox is a mathematician not an astrophysicist, not that it matters to McGillis. “Math was never a great interest of mine,” says McGillis, a high school dropout who later entered Juilliard as an acting student. “Still isn’t.”

Cruise and McGillis meet during a lecture, and their love soars like a ground-to-air missile. Fox says that in her experience quite the opposite happens when she talks ship with the guys. “The fact that I know so much about what these guys are doing every day and they come in and talk to me about it—why is my radar doing this?—changes the relationship. It takes some of the romance out.”

In fact, the unmarried Fox has never become involved with an aviator, a state of affairs that has not gone unnoticed by the aviators. Captain Smith figures that “she’s a genuine straight arrow.” Comdr. Harry Hunter, who works in the same office, says “She’s so professional that her looks don’t become a point of interest. When she walks in you say ‘wow,’ but 30 seconds later you’re talking business.”

Fox often goes to the Officer’s Club after work, and she usually is looking around for aviators, but the conversations are more technical than titillating. Over a few drinks the fliers loosen up, and she learns what’s really on their minds. “When I debrief these guys, it’s very formal and they all want me to know what a good job they did,” she says. “At the Officer’s Club, they’ll talk forever.”

In her pursuit of information Fox has flown in B-52s and the E-2C early-warning aircraft, observed exercises from the aircraft carrier Kennedy and taken water-survival and ejection-seat training. Through it all she never fails to absorb an enormous amount of teasing about her looks. “The reason it doesn’t bother me,” she says, “is that it doesn’t interfere with the work. It’s just part of an attitude all aviators subscribe to, something they adopt as soon as they join the fighter community. If that prevented them from coming over and asking for help, then it would be a disaster.” She smiles sweetly. “Anyway, I make fun of them for being macho creeps sometimes.”

Lt. Linda Speed, an administrative officer at the TOPGUN school, has another theory on sex and the single pilot. “These guys compartmentalize their lives,” she says. “Flying is in one box. Women and dating are in another. Sometimes it’s hard for them to put work and women in one box.” The atmosphere at TOPGUN is so masculine that when Fox walks over on business, the guards sometimes ask whether she’s there to pick up her husband’s check.

Fox probably wouldn’t have ended up in this line of work had it not been for her father, a retired naval nuclear engineer who encouraged her to pursue mathematics. An only child, she grew up in northern Virginia and later studied at George Mason University in Fairfax, Va. While she was there, General Research Corp. contacted the math department looking for a candidate to be a junior analyst. She was recommended and after graduation, took the job. At night school she earned a master of science degree in applied mathematics, and in 1981 she joined the Center for Naval Analyses.

Fox is in the final days of her tour at Miramar; this week she returns to CNA headquarters in Alexandria, Va., where she will work as a research study director. When she arrived two years ago, says Commander Hunter, the attitude in operations was, “God, we’re going to get stuck with a girl.” Now that she’s being replaced, he says, the attitude is, “God, we’re going to get stuck with a guy.”