Why 'smart' bombs don't end friendly fire

This week's killing of American troops by American bombs in Afghanistan illustrates the old dangers of new technologies.

In the battlefield of the 21st century - with advanced systems designed to distinguish friend from foe, near-instant intelligence and communication and weapons guided by satellite and laser beams to within feet of their intended target - it's still possible to have casualties caused by friendly fire.

In the latest example, three special forces soldiers were killed this week, in the largest single loss of American troops thus far in Afghanistan, when a guided bomb missed its mark.

In the "fog of war," incidents of "fratricide" - also known as "blue-on-blue" casualties - are not uncommon. Civil War historians still wonder whether the accidental wounding and consequent death of top Confederate General Thomas "Stonewall" Jackson by his own troops may have changed the outcome of that conflict.

During the Gulf War, nearly one-fourth of all allied casualties were due to friendly fire. Most of those deaths resulted from tank battles in which targets were misidentified. And in 1994, a pair of US Air Force F-15 fighters patrolling the Iraqi no-fly-zone mistook two US Army Blackhawk helicopters for Soviet-made Iraqi aircraft. Both helicopters were shot down, and 26 lives were lost.

Lieutenant Colonel Scott Snook, a professor at the US Military Academy at West Point (and himself the victim of friendly fire during the US invasion of Grenada in 1983) has studied the phenomenon of friendly fire in detail.

In his recent book, "Friendly Fire," describing the helicopters shot down over Iraq, Lt. Col Snook found that, "no smoking gun emerged." "There weren't any bad guys; hence, no one to blame. There weren't any catastrophic failures of material or equipment; hence, nothing to fix. The more I looked for traditional culprits, the more I realized that this accident occurred not because something extraordinary had happened, but rather just the opposite."

This incident of tragic fratricide, he concluded, was not an accident but resulted from a series of small failures to communicate information, use common radio frequencies, and coordinate activities.

The cause of this week's accidental bombing of US Army special operations troops in Afghanistan remains to be seen. What's known is that a US Air Force B-52 at high altitude dropped a 2,000-pound bomb called a JDAM (Joint Direct Attack Munition).

This is basically a traditional iron gravity bomb with a specialized tail kit. The addition steers the bomb to the target using geographic coordinates and Global Positioning Satellites (GPS). If everything works (which it has in 95 percent of drops as well as in

combat in Kosovo), the bomb should hit within 13 meters of its target. That was not the case Tuesday when a JDAM landed within 100 meters of US forces, killing three Americans and six Afghan anti-Taliban soldiers and injuring about 40 others.

With such very large bombs, military officials say, friendly forces should be at least a quarter of a mile away.

Among the possible causes of this accident: US ground controllers gave the B-52 the wrong target coordinates, the B-52 crew entered mistaken coordinates into their weapon system, or the bomb's guidance system failed. It could also have been something as simple as a bent tail fin.

"We have not perfected a technology that is perfect in its execution," Rear Admiral John Stufflebeem, deputy director for operations for the Joint Chiefs of Staff said at a Pentagon briefing. "These are human-made, human-designed systems, and therefore, they're going to have flaws that are going to either be built in or that are going to occur."

This week's accident was not the first involving a JDAM. The same ordinance injured five US servicemen at Mazar-i-Sharif recently when US bombs were used to end a prison uprising by Taliban soldiers. There have also been several reports of civilian casualties caused by US precision bombs missing their targets. US officials, however, are reluctant to accept any responsibility for those bombings.

"With the disorder that reigns in Afghanistan, it is next to impossible to get factual information about civilian casualties," Defense Secretary Donald Rumsfeld said at a Pentagon briefing this week. "We know this much for certain: the United States has taken extraordinary measures to avoid civilian casualties in this campaign."

Still, village authorities and American journalists have reported many civilian deaths and injuries from bomb attacks.

The Pentagon is working on systems to avert friendly-fire casualties by improving what's called "situational awareness and target identification."

One such "don't shoot me" system, as the Defense Department calls it, would involve small global positioning and millimeter-wave devices that would help troops on the ground and in the air identify each other. It would not, however, distinguish civilians or other neutrals from the enemy.