Pentagon Probing Electronic Interference Suspected in F111 Crash During Libya Strike

Mixed Signals May Have Misguided U.S. Weapons
by Mark Thompson

Source: The Washington Post

January 22, 1989

When U.S. warplanes. were ordered to, strike Libya in 1986, they ran into an electronic blizzard that Pentagon officials now suspect might have caused one of the fighters to crash and others to miss their targets.

The disruption came not from the Libyans, but from high-powered U.S. military transmitters that filled the night sky with electronic signals designed not only to enable the fighters to communicate but to jam Libya’s antiaircraft defenses, hunt targets, and guide weapons.

The Pentagon is so alarmed by the problem it has launched a $35 million effort to identify the interference and keep it from happening again, according to Air Force Col. Charles Quisenberry, who is leading the probe. The study is expected to take three years.

During the Libyan strike, U.S. weapons "were interfering with each other and they [U.S. commanders] came back out of that and they said: ’Look, we’ve got some problems here, and we want to know if we’re doing it to ourselves, or if the bad guys did. it to us,’" Quisenberry said in an interview. "The end result was we found out we did it to ourselves."

President Ronald Reagan ordered the April 1986 strike after U.S. intelligence linked Libya to the terrorist bombing of a West Berlin nightclub’ in which a U.S. serviceman was killed.

During the attack, 18 Air Force and 15 Navy planes attempted. to strike five targets after U.S. planes and ships saturated the air with powerful electronic transmissions.

Quisenberry said radio-wave interference might have led to the downing of an F111 jet fighter, whose two crew members were the only U.S. fatalities in the attack.

Numerous U.S. weapons, some of which were electronically guided, went astray during the attack, damaging three foreign embassies and diplomatic residences, including those of France and Japan. And several of the 32 surviving planes including five F111s aborted their mission without firing a shot because of unspecified problems. Recent Pentagon studies have shown that some combinations of U.S. weapons transmitting radio waves at certain frequencies can bring down U.S. warplanes, Quisenberry said.

Some radio waves common above the battlefield "will actually affect the electrons within the aircraft’s flight controls as well as its fuel controls," he said, either putting a plane into an uncommanded turn or dive or turning off its fuel supply.

Quisenberry recently finished a classified seven-month investigation of the problem which led top pentagon officials to order the more detailed three-year study.

"There are major, major problems out there that need to be addressed." Quisenberry said. "The proliferation of equipment that operates in the electromagnetic spectrum keeps growing. It’s finally gotten to the point where we’ve got to do something about it."

Quisenberry and his staff of 65, working from the Tactical Air Warfare Center at Eglin Air Force Base in the Florida panhandle, will study the Pentagon’s primary war plans. For the first time, they will calculate how radio emissions from the weapons of one service might disrupt the sophisticated electronic gear of the other services.

Before conducting tests on weapons in the field, Quisenberry’s study is using computers to detect problems.

A preliminary study of one war plan revealed "thousands of (radio wave) conflicts" among the weapons slated to be used in the event of a war in that region, Quisenberry said.

"Many people have told us that a lot of people will not be happy with what we find out because we’ll actually uncover problems," he said. "If there’s a problem with the B1, that might not be politically acceptable-people may have some heartburn with that."

He said his goal is to inform U.S. and allied commanders of potential problems and recommend tactics to avoid them-either by assigning new frequencies to certain weapon transmitters or assuring that conflicting weapons are kept far enough apart to prevent interference.

Tests using weapons "where we can turn the equipment on full blast" are to begin. this summer, Quisenberry said.

In the past, he said, the Pentagon too often ignored its safeguards designed to protect weapons from electromagnetic interference (EMI).

"In many cases, a program manager will get an exemption for. getting a weapon delivered without having EMI looked at completely;" Quisenberry said.

Such waivers have been "a kind of run-of-the-mill thing, to be honest with you," he said. "In many cases, you have politics involved in getting a product developed, or a program manager has a schedule to meet. The most important thing is that there was not a hammer-someone saying you could not build a certain weapon until its EMI problems were fixed."

Last year, the Army acknowledged that flight near large transmitters could put its UH60 Black Hawk helicopter into uncommanded turns. The service has begun a $175 million program to shield the Black Hawk’s flight control computers from such radiation. Since 1982 as many as five UH60 crashes that killed 22. servicemen may have been due to electromagnetic interference.

"The Black Hawk was shielded at a very low level - it was known ahead of time that its shielding was inadequate," Quisenberry said. "There was a lot of corporate knowledge that knew it wasn’t going to hack it."

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