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Grange: Fratricide common in war

David Grange is a former U.S. Army major general and now a CNN military analyst.

UPDATE: Friendly fire incidents such as the one that killed three U.S. and six anti-Taliban soldiers near Kandahar are known as fratricide. This happens in every conflict. We are getting better and better at avoiding it, but no matter how high-tech you get with positioning devices, lasers and such, these things will occur as long as humans are involved.

IMPACT: You want close-air support close or else it's not going to be effective -- basically as close as you can get without hitting your own people. Of course, that increases the danger level. The Pentagon said U.S. and opposition forces were facing Taliban mortar fire, so the enemy probably wasn't far away.

Because they were receiving mortar fire, they just pulled out whatever was available in the sky -- in this case, a B-52. This isn't surprising, because these aircraft were probably circling the area and when you're under fire you just want something right away. If given the choice for close-air support, I'd probably want an AC-130 gunship, which is much more precise.

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Also, shrapnel from a 2,000-pound bomb -- like the one used here -- can go a long way and cause a lot of damage. I have been on the ground when a "dumb bomb" (without any guidance system) hit a kilometer away and I was petrified. So the casualties weren't all necessarily hit directly.

TACTICS: Here we have a B-52 bomber and a 2,000-pound JDAM bomb -- joint direct attack munitions. It doesn't have a terminal guidance capability, in which you have a continuous beam on the target and as the bomb goes out it homes in on the beam. Instead, B-52s use a combination GPS, or global positioning system, and INS, an inertial navigational system that measures winds, altitudes and other factors.

In this case, it's all pre-set when someone on the ground gives geographical coordinates that are eventually sent by a satellite to the B-52. Once the information is plugged in, the bomb goes wherever it's planned to go. But you could have had a mechanical problem. Or maybe the man on the ground gave the wrong geographical coordinates relative to where friendly forces are situated.

An eight-digit military grid coordinate is within 10 meters, six digits is within 100 meters. If you're off by just one digit, it makes a big difference. Also, data for GPS systems can be different in different places around the world, further complicating matters. If a mistake is made somewhere in the process -- let's say, someone plugged in the coordinates wrong -- then it's not correctable.

Basically, there's a lot to it, and mistakes are made. But with all the advancements, it's very rare you have casualties -- maybe one in 1,000 times.

STRATEGY: This was a pretty big American unit that was hit, as special ops usually operate in much smaller groups. The special ops could have been with Air Force specialists, or the site could have been the Special Forces' forward operating base.

Given that Hamid Karzai -- the leading anti-Taliban Pashtun figure in the south who was just named head of the Afghan transitional government -- was reportedly injured, it's also very possible this could have been a meeting of U.S. forces with the so-called Southern Alliance. They may have all been setting up liaisons and planning an upcoming attack on Kandahar.

EDITOR'S NOTE: CNN is sensitive to reporting any information that could endanger lives or operations.