The Air Force is shifting its strategy to combat enemy fighters in Afghanistan after commanders ordered a review of a joint U.S.-Afghan air strike that the Afghan government said killed 90 civilians in August.

Military commanders at Bagram Air Base, north of Kabul, say they're employing new procedures to "amplify" what the Air Force was already doing to avoid civilian casualties, such as using a fly-by tactic with F-15 attack Eagles to scatter anti-coalition forces.

The strikes in August were called in by American Special Forces using an AC-130H gunship, also known as a Spectre. It uses computer tracking and targeting equipment to fire 105mm howitzer, 40mm bofors, and 20mm Vulcan cannons -- a very deadly aircraft to be deployed in a civilian area.

Initially, despite video showing the bodies of women and children, the U.S. Army claimed only five to seven civilians were killed in the attack on Afghan militants. Now a U.S. military investigation has concluded that at least 33 civilians, including 12 children, were killed.

Fighting in Afghanistan has intensified in recent past months. On Sunday, Gen. David McKiernan, the top U.S. commander in Afghanistan, rejected media reports that the alliance was losing the war against the Taliban and called on troop-contributing countries to send more soldiers and military gear in order to achieve success more quickly.

A senior Western diplomat here said American forces are waging a fight in a complex environment. "In this calendar year there were more than a thousand nighttime raids. Yes, some horrible mistakes, but only three incidents like that."

He added: "We regret every one of the three, but 997 raids went right."

But clearly the Afghan government's reaction to public outrage has forced American commanders to tighten the rules on air strikes.

Click here to read OnTheScene blogs from Dana Lewis and his team in Afghanistan.

Brig. Gen. Mike Holmes, commander of the 455th Air Expeditionary Wing, paints a moving picture of what his pilots have to deal with at high speeds and in difficult terrain.

He said they're called in -- usually at night -- to assist troops in contact with the enemy who could be overrun by insurgents without air cover. "We have one third of the planes in Afghanistan than employed in Iraq, but we drop three times the number of bombs," he said.

That, he said, is because there are few roads in Afghanistan. If U.S. soldiers need help, it can take hours or days to arrive on the ground. Air power, he said, "can be there in five or 10 minutes."

Holmes said the new procedures are "almost the same as we were doing before, but with a few exceptions."

He points out that 2,000 aerial attacks have occurred this year, ranging from a strafing run, to bombs being dropped. But he said there have also been 2,000 "shows of force" -- when the Air Force simply calls in its F15s or A-10s, and the low altitude, high-speed pass is enough to get the insurgents to scatter.

"Five hundred feet at 500 miles an hour on top of a fight will calm it down pretty quick," he said.

At Bagram, a weapons officer nicknamed "Pipper" discusses the flights. She sits behind the pilots and handles the weapons system. She monitors a "death dot" on the F-15 weapons screen that indicates where rounds will land if fired.

Pipper says the pod on the belly of the aircraft allows her to see anything during night missions. As if she were using a camera, she can adjust and zoom in or out and clearly see her target.

She said that "if there are civilians, if the area is not clear," they will not drop bombs. They take a pass, or they loiter high above until a vehicle carrying insurgents leaves the town or village before striking a deadly blow.

Some of their questionable air strikes have been in support of Special Forces troops who order a strike on a target. The Special Forces say they have "eyes on" so the Air Force responds.
But that's no excuse for a bad strike, and the Air Force does not offer it as a reason.

But to ignore that fact would be to not fully understand how tragic incidents happen when pilots and weapons officers are flying at 500 feet and 500 miles per hour, making split-second decisions.

Most of the time, they get it right.