Air Battles Won Behind Closed Doors : Defense: The Benefield Anechoic Facility, used for testing planes at Edwards Air Force Base, is receiving a $200-million upgrade.

In an immense steel vault bathed in eerie blue light and protected around the clock by armed guards, the Air Force’s latest fighter jet was recently tricked into thinking it was in the heat of high-tech combat.

The F-16 Falcon sat motionless on a huge turntable as computer technicians bombarded it with electronic signals mimicking enemy missiles and radar stations, simulating a flight over hostile territory.

The fake mission was staged in the Benefield Anechoic Facility, a computer-stuffed building where sophisticated electronic gear intended to help American military pilots outmaneuver future enemies is tested. The facility is the largest of its kind in the world.

Enclosing 4.6 million square feet of space, the Benefield chamber is spacious enough to hold virtually any U. S. military airplane, including the B-1 bomber. Planes are rolled in through one of the world’s biggest doors, a 250-ton steel device that is so bulky it takes 40 minutes to close.

As Congress cuts funds for defense facilities around the nation, the Benefield complex is in the enviable position of undergoing a $200-million upgrade that began last year and is scheduled to last another seven years--the most expensive improvement of any U. S. military test facility.

But the chamber also is the focus of an ongoing tug-of-war in Washington over how to spend increasingly scarce military research funds. The Navy operates a similar chamber in Maryland, and members of Congress from California and Maryland have squabbled over which one should get more federal dollars.

The Benefield chamber is a strange-looking place, with thousands of small blue spikes protruding from nearly every square foot of its walls, floor and ceiling. With overhead spotlights barely piercing the gloom, a visitor might mistake it for some vast, heavy-metal concert hall.

Made of foam, the pyramid-like spikes absorb stray radar signals that bounce off aircraft during tests of electronic warfare devices, which allow military jets to detect, evade and jam enemy radar and missiles.

Although some testing must be done in flight, the Benefield facility allows engineers and computer scientists to work out some bugs on the ground, which is cheaper and safer. Also, precision measurements can be made repeatedly in the chamber, something that is very difficult to do in the air. Edwards, located about 100 miles northeast of downtown Los Angeles, is the Air Force’s premier flight test facility.

“We’re trying to get out of the fly-fix-fly syndrome,” said Mickey R. Brown, a retired Air Force captain and flight test engineer who is the civilian chief of testing at the chamber, which employs about 70 people.

Sealed in steel, the facility is a “sterile” test environment, keeping out the multitude of radio, TV and radar signals that could strike a test aircraft if it were flying over Edwards and such nearby residential areas as Palmdale and Lancaster.

The steel also prevents electronic signals from classified military transmitters from leaking into the open air. While Air Force officials believe the threat of espionage has diminished with the Soviet Union’s collapse, electronic combat signals theoretically could be picked up by foreign satellites or spy ships.

The Air Force spent $82 million to build and equip the chamber, which opened in 1989. It is named for Tommie D. (Doug) Benefield, former chief test pilot for Rockwell International, which built the B-1, the first aircraft to be tested there. Benefield died in a B-1 crash in 1984.

With so much classified work going on inside, the chamber is protected 24 hours a day by armed guards. Engineers, scientists and technicians are issued plastic cards that allow them access only to rooms where they have specific clearance.

So elaborate is the security system that if workers try to use their cards to get into a room where they aren’t allowed, their names are automatically printed out in the guards’ control room. Air Force officials recently allowed a Times reporter and photographer to tour the chamber, but only on a day when no aircraft were in it.

But as defense downsizing continues, the Benefield facility has been caught in an ongoing struggle in Congress and the Pentagon over how to spend federal funds on electronic warfare testing.

Its chief rival is the Naval Air Warfare Center in Patuxent River, Md., where the Navy has its own, smaller anechoic chamber. Maryland’s well-organized congressional delegation has pushed hard for more funding for Patuxent River, while members of Congress representing Southern California have pushed for Benefield.

Although many defense experts think the Air Force and Navy could get along with one chamber, the Pentagon--under congressional pressure--has issued a stream of confusing and contradictory reports about which chamber should be funded.

After a Pentagon-hired consultant in 1992 recommended developing Benefield as the “least costly alternative,” Maryland representatives asked the Pentagon’s inspector general to review the consultant’s report.

The inspector general said the report “contained critical flaws,” and urged that equipment be reallocated to both Benefield and Patuxent River from other locations. Later, a top Pentagon test official rejected the inspector general’s findings.

To date, none of the aircraft tested in the Benefield chamber has seen combat, Brown said. But that is likely to change the next time U. S. jets are committed in wartime.

During a test, computer operators beam signals at aircraft in the chamber through three loudspeaker-like “threat emitters” mounted on the walls. The signals electronically imitate enemy jets, missiles and radar stations.

“You stick the airplane in there and make it think it’s on a real mission,” said Richard Hansen, program director for Edwards’ Electronic Combat Integration Test Program.

Technicians operating the threat emitters can select from a library of signals representing radar devices from other nations. Austin Page, Edwards’ intelligence director, said how the foreign signals are gathered is classified. Brown said new signals are delivered to the base each month.

Much of what goes on in the chamber involves testing high-tech gear that lets U. S. pilots jam enemy radar or electronically camouflage their plane’s location--a tactic known as “spoofing.”

As military jets fly faster and air warfare becomes more high-tech, pilots must know quickly if their planes have been “painted” by hostile radar--a telltale sign that enemy fighters or missiles are on the way.

Warned, a pilot can take evasive action, launch decoys and jam or spoof enemy radar. If enemy technicians boost power or switch frequencies to beat the jamming, the pilot must counter the countermeasures.

“It’s a big chess game done with electronics,” said Brown. “They come up with a threat, you come up with a countermeasure. And it all happens very fast.”

But a powerful military jamming machine can disrupt civilian communications, interrupting traffic-control radar at airports and football games on TV. Such mishaps have occurred at Edwards, but with testing in the chamber, they are a thing of the past, said Jim Rizzo, the base’s range frequency manager.

“The last thing you want to see is a jammer come up on your TV station,” said Rizzo. “It’s a major problem at 2 in the afternoon when someone’s trying to watch the soaps.”