Usually precise, smart bombs do carry risks

WASHINGTON -- Guided by satellite, the military's newest "smart bomb" is designed to hit its target with great precision in any weather.

The system is not without risk, as was evident Wednesday in Afghanistan, with deadly results for the U.S. military: three soldiers killed, 20 others wounded when a bomb carrying 2,000 pounds of explosives landed about 100 yards from their position.

"Sometimes things just don't work out perfectly," Rear Adm. John Stufflebeem said at the Pentagon.

"These are human-made, human-designed systems. They're going to have flaws that are going to either be built in or that are going to occur. We have not perfected a technology that is perfect in its execution."

It was unclear how the bomb intended for Taliban militia hit teams of special forces and anti-Taliban fighters.

The weapon was a JDAM, or Joint Direct Attack Munition. A $20,000 kit attached to the tail of a conventional 1,000-pound and 2,000-pound warhead is supposed to produce a guided glide bomb, accurate to within at least 30 feet.

The JDAM can be launched from 15 miles away and an altitude of 45,000 feet. It was developed after the Persian Gulf War showed the need for precision weapons that would not be affected by clouds or any kind of conditions.

The incident Wednesday was the third JDAM mishap known so far in the anti-terrorism campaign in Afghanistan. The Pentagon says it has used 3,500 of those bombs against the Taliban and al-Qaida terrorists.

One accident in late November in which five Americans were injured is under investigation. In early October, four Afghans were reported killed because someone gave the wrong coordinates for the target, the Pentagon has said.

Possible reasons

Possible explanations for Wednesday's accident: special forces on the ground called in incorrect coordinates for the strike; the coordinates were entered incorrectly into the bomb delivery system by someone on the Air Force B-52 that dropped the bomb; or the weapon malfunctioned.

"The JDAMS are very accurate weapons," said Bob Algarotti, spokesman for the contractor, Boeing Corp. The bomb is only "as accurate as the coordinates it's given," he said.

Asked if the latest accident gave reason to be skeptical about JDAM's accuracy, Stufflebeem said it is not. The former pilot said the military and the public have come to expect extremely high standards from new technology and that Wednesday's mission was one of the most dangerous there is.

"As a pilot, I can do everything perfectly with a perfect weapon system, and still cannot account for every weapon going exactly where it's supposed to go," Stufflebeem said. "And that's just a fact of unfortunate life here in this case."

"This is one of the potentially most hazardous types of missions that we use as a military tactic -- calling in air strikes nearly simultaneously ... on enemy forces that your engaged in close proximity to," he said.

Stufflebeem said in such a mission a person on the ground signals where he is, and where and when he wants a bomb dropped. That information is put into a computer on the plane that tells the bomb where to go. The bomb uses the satellite system to guide it toward the target.

Errors can occur

When a strike is called in, coordinates can be given by radio with voice message or signals -- which might be misunderstood. Or they can be sent from computer on the ground to computer on the plane -- which can go wrong if numbers are typed incorrectly.

The weapon is being used by the Air Force and Navy in Afghanistan. It was first used in Kosovo in 1999 when two B-2 stealth bombers dropped 16 of them.

During 1998 and 1999 testing, it was found to be accurate to within 9.6 meters -- meaning 50 percent of the bombs would fall within an average of about up to 30 feet from the intended target, the Air Force says. Because the blast area is massive -- some 4,000 feet -- being off by 40 feet would still be a hit, experts said.