U.S. Risking Its Hard-Won Stealth Secrets in Gulf War : Aircraft: But steps have been taken to protect much of the technology if one of the F-117A fighters goes down.

When a Lockheed F-117A crashed near Bakersfield in 1986, the Air Force cordoned off the site with armed guards, closed the airspace overhead and spent a month hauling away wreckage in a frantic effort to protect the secrecy of the aircraft.

But if an F-117A goes down in Iraq, where it has excelled in nearly 1,000 precision bombing missions, the world’s most advanced combat jet would fall into the hands of the Iraqis and perhaps other potential adversaries curious about U.S. capabilities.

The U.S. military has spent billions of dollars to pioneer and dominate the technology of Stealth, which enables U.S. pilots to elude detection by enemy radar. While at other times in military history secret weapons have been held back, the United States has decided this time to deploy its most powerful technology despite the risks.

To protect the vast investments in Stealth, the secrets of the F-117A are known only to a few U.S. civilians and their military counterparts. The most critical information has been programmed into computers far from enemy lines, rather than put at the fingertips of military tacticians.

Indeed, the aircraft’s innermost Stealth secrets have not been disclosed even to pilots who fly the F-117A, preventing disclosures of technology if pilots are captured and interrogated.

“Pilots don’t know what the radar detectability is,” said an F-117A expert. “That is very tightly held. There are very few people who know. There are very few people in the Air Force who know.”

The Stealth is not infallible, and if an F-117A does crash behind enemy lines, it would almost certainly become the target of U.S. bombing.

“The F-117A can be seen and can be defeated,” said Lt. Gen. Thomas R. Ferguson Jr., the Air Force’s chief of aircraft development. “If you had a crashed airplane, they (Iraqis) could exploit it. It wouldn’t surprise me if we went to some lengths to avoid that. We might put in a mission behind it to actually bomb the wreckage.”

The plane does not contain a self-destructive charge to blow it up in the event of a crash because that would be unacceptably hazardous to pilots, according to the F-117A expert, who declined to be named.

Since F-117A pilots have limited information about the plane’s technology, the source familiar with the aircraft said they could compromise few of its secrets. Still, they are familiar with the Stealth’s secret speed, range and payload, and the disclosure of such secrets during interrogations by captors is regarded as an inevitable cost of using the weapon.

CIA pilots who flew the U-2 spy plane during the 1950s were given hypodermic needles to inject themselves with poison if captured, but Air Force pilots have never been asked or given the option of committing suicide, according to aeronautics experts.

Air Force and Lockheed officials declined to answer any questions about the potential loss of F-117A technology in the Gulf War.

“That program is off-limits right now,” said a Lockheed spokesman. “It is still a black program as far as we are concerned.”

Despite the potential for losing the F-117A’s secrets, the imperative to use the aircraft against Iraq was clear.

“People don’t want to go against Saddam Hussein with second-class weapons,” said one expert. “The threat is sufficient to release the use of our very highest technology weapons.”

The decision to risk exposing the nation’s most advanced military science to the outside world is a dilemma that the United States always has faced with great difficulty.

During World War II, both the Allies and the Germans refrained from using certain technologies for fear of disclosing secrets to the other side.

Each side, for example, discovered that radar systems could be defeated by small strips of radar-reflective metal, later called chaff, dropped from an airplane. But neither side used the idea, fearing the loss of their own radar capability if the opponent used the same tactics.

“We probably lost a lot of crews needlessly because we didn’t use it,” said a defense industry radar expert.

In the Korean War, the Air Force declined through most of the hostilities to use its Lockheed F-94 Starfire fighter, out of fear that the plane’s radar--built by Hughes Aircraft--would fall into Soviet hands.

Such conundrums are not unique to modern times.

“Various societies throughout history have always faced a challenge in deciding when to utilize their latest and best technology,” observed Richard Hallion, an aeronautics historian at the Smithsonian Institution.

In the 15th Century, the Byzantine Empire developed a self-igniting, napalm-like weapon known as Greek Fire.

“It was the atomic bomb of its era,” Hallion said. “It was so destructive, and the Greeks so feared that its secrets would fall into the hands of the enemy, that it was rarely used.”

Eventually, the Byzantines lost the capability to make the secret weapon as the result of a clan feud. They were defeated in 1453 by Turkish forces who had obtained a new weapon of their own, Hallion said--the cannon.

Efforts to build devices that destroy weapons in the event they are captured have not worked well. During World War II, engineers once tried to use vials of acid to destroy secret radar gear, but pilots objected to the hazards.

In the Gulf War, the United States has committed the full breadth of its high technology, including laser targeting, night vision, ground-imaging radar and a host of other electronic systems. The United States is the undisputed leader in such electronic weapons and in Stealth.

Some experts believe that even if such systems as the F-117A fall into Iraqi hands, they would be of little immediate value.

Eugene Gritton, a deputy vice president at RAND Corp., said Iraq would have difficulty duplicating the F-117A’s capabilities, even if it had the chance to examine the wreckage of a Stealth fighter.

“You would still have to build the aircraft in quantity and at an affordable price, which is not easy to do with that kind of technology,” Gritton said. The F-117A was built at a cost of $100 million per aircraft, including the research and development that preceded production.

“It’s pretty hard to reverse-engineer this technology,” added another Stealth expert. “These people don’t have that much technical capability. Plus, this aircraft’s technology is now 10 years old.”

Although the F-117A has Stealth technology that is a decade older than that in the B-2 Stealth bomber, it is vastly superior to anything flown by any other nation’s forces. It is also the only operational Stealth fighter the United States will have for at least another decade.

Even a nation more technically advanced than Iraq might have difficulty engineering a Stealth aircraft by examining an American F-117. But such an adversary could glean ways to defeat the aircraft by examining its materials and construction. Experts say a number of arms producers would be interested in its electro-optical sensors--including infrared targeting systems, which remain highly classified.

The F-117’s innermost secret is its so-called “radar cross-section”--in other words, the size of the target it provides to an enemy radar. The radar cross-section is a function of the physical shape of the aircraft, its size, the materials it is made of and its internal construction.

It is determined, too, by the enemy’s radar frequency, the radar’s power, the angle of the aircraft relative to the radar and a host of other variables.

None of that information is known to U.S. fighter pilots.

“We have all that in a computer so the pilot doesn’t have to think about it,” one Stealth expert said. “Anyway, how can a man know all that?”

In any event, Gritton believes that since the U.S. defense research effort is robust, new systems will be forthcoming that are even more capable than the F-117A, making it pointless to hold the fighter out of the current hostilities.

“We certainly want to use this technology,” he said. “Why else would we have developed it if we didn’t intend to use it, especially in this kind of environment?”

Times staff writer John M. Broder contributed to this report.