‘Friendly Fire’ Still a Factor in Battles

Since the Persian Gulf War, when 25% of U.S. combat fatalities were caused by American forces, the Pentagon has worked mightily to solve the devastating problem of “friendly fire” casualties.

Despite those efforts and the increasing precision of U.S. bombing technology, military officials and experts acknowledge that fratricide--the military term for deaths caused by friendly fire--remains a feature of modern warfare.

And they say that the kind of front-line incident that killed three Americans and five Afghans and injured 20 Americans and 20 Afghans on Wednesday is among the most difficult to correct.

To avoid tragic mix-ups, U.S. forces have adopted new methods to make American vehicles identifiable to other forces on the ground. Tanks and personnel carriers are supposed to have thermal panels that make them highly visible, and identifiable, through infrared sights at night. Individual soldiers can wrap their helmets in the same thermal material to make them stand out.

In the sky, U.S. aircraft carry electronic systems that give off signals identifying them as friendly.

Yet the problem of making small units of ground troops identifiable from the air is far more complex.

From an altitude of 40,000 feet--the height at which the B-52 was probably flying Wednesday when it dropped the bomb that killed the Americans--the thermal panels have no value.

One day, all U.S. forces will be able to keep track of one another through common “battlefield awareness” computer systems now under development. But their completion is a long way off.

U.S. officials say they do not know what caused Wednesday’s accident. Although U.S. bombing systems become more precise with each war, human error and mechanical failure can still creep in.

The satellite-guided bombs called Joint Direct Attack Munitions (JDAMs) that were involved in the friendly-fire incident are considered by the Pentagon and outside experts to be a highly precise technology. The bomb is designed to strike within about 15 yards of its target after U.S. military personnel punch in the map coordinates; in practice it is more precise, usually hitting only about four yards away.

Yet in the confusion of battle, targeters can punch in the wrong figures. This has apparently happened on several recent occasions.

Such a mix-up was responsible for the mistaken bombing Nov. 26 at Mazar-i-Sharif in which five U.S. soldiers were injured. In that incident, the coordinates were reversed, and a 500-pound bomb struck near U.S. troops.

The same kind of human error apparently caused a mistake in the first days of the war, leading a Navy F/A-18 to drop a bomb on homes near Kabul, Afghanistan’s capital.

Such errors can arise as coordinates are passed along from controllers to air operations centers to air crews. They can be caused by misreading maps or by errors in the maps themselves, experts say.

In addition, the bombing equipment can fail for several reasons.

A tail fin can break off, causing the bomb to veer wide of its target. The electronic link to satellite signals can be interrupted, throwing the bomb at least slightly off course. The software can fail.

The likelihood of mechanical failure on JDAMs is about 5%, experts say.

Richard J. Dunn, a retired Army colonel, said the accuracy of JDAMs is “just phenomenal.”

Even so, he said, “when you’re dropping 2,000 pounds of bomb through tens of thousands of feet, even all of this technological wizardry can’t guarantee that nothing will go wrong.”

Analysts said it was also possible that the location of the U.S. Special Forces was misreported, through a mix-up, a technological failure or the misreading of a map.

They pointed out, however, that the use of a 2,000-pound bomb for close air support was unconventional. Typically, such large bombs are used to strike larger fixed targets, such as bridges or buildings, rather than smaller mobile targets, such as enemy troop units.

One consequence of using larger bombs is that they spray shrapnel long distances.

Troops are considered at risk from a 2,000-pound bomb even at a distance of about half a mile, Dunn said. In this incident, the U.S. forces were only about 100 yards away, according to U.S. officials.

William Arkin, a military analyst and retired Air Force officer, said the incident occurred in one of the most dangerous places on the battlefield--the “seam” between the two forces.

Like many in the military, he considers some risk unavoidable.

“It’s unremarkable that there was an incident here,” he said. “What’s remarkable is that there have only been four people killed [in combat] in this war to date.”