A new Pentagon report concludes that while fratricide or so-called friendly fire accidents are likely during battles like those that occurred in Iraq when the skies were crowded with friendly aircraft, the Pentagon still must take more steps to limit the risk of such incidents in the future.

According to a summary of a report issued by a Pentagon advisory panel, Patriot missile systems used during battle in Iraq were given too much autonomy, which likely played a role in the accidental downings of friendly aircraft. Troops operating those systems should have played a greater role in choosing targets, according to the report.

Other factors contributing to the accidents included combat identification systems that performed poorly and an inability to bring together data from the Patriot radar and other sensors on the battlefield.

The “Report of the Defense Science Board Task Force on Patriot System Performance,” which was published in January, is classified. However, the Defense Science Board posted a summary of the report on its Web site in early March.

Despite the fratricide accidents, the board described the Patriot’s performance in missile defense in Operation Iraqi Freedom as a “substantial success.”

The Defense Science Board is an independent advisory committee that advises the secretary of defense. Michael Wynne, acting undersecretary of defense for acquisition, logistics and technology, commissioned the panel to report on the fratricide incidents during Operation Iraqi Freedom in June 2003 following two fatal accidents and one close call.

In March 2003, a Patriot missile destroyed a British Tornado fighter bomber, killing its two pilots. Two days later, a Patriot battery locked on to a U.S. F-16 aircraft. The following week, a Patriot missile struck a U.S. Navy FA/18 Hornet, killing the pilot.

The Patriot batteries were originally designed to shoot down aircraft rather than missiles, but their mission in Iraq focused on the latter. The report found that the crowded skies over Iraq made picking out ballistic missiles from aircraft a difficult challenge.

The U.S.-led coalition launched about 41,000 sorties of friendly aircraft over the 30 days of major combat operations, while the Iraqi military launched nine tactical ballistic missiles during that period, according to the report.

The Defense Science Board found that most of Patriot operations are autonomous, with operators trained to trust the system’s software.

“The solution here will be more operator involvement and control in the functioning of a Patriot battery, which will necessitate changes in software, displays and training,” the report stated.

Guy Shields, a spokesman for Raytheon Integrated Defense Systems of Tewksbury, Mass., which builds the Patriot system, said that the Defense Science Board report validated that the system performed as designed, but declined to comment further.

Maj. Desiree Wineland, an Army spokesman, did not respond to requests for comment by press time.

The report also found that systems in coalition aircraft that identified them as friendly forces “performed very poorly.”

This should have come as no surprise, as the poor performance had already been on display in many training exercises, and the task force stated that it was “puzzled” that the problem had not been corrected earlier. In addition to fixing the combat identification systems in the aircraft, coalition forces should consider taking additional measures including designating safe return corridors for aircraft, the report said.

The Patriot’s mission was further complicated by difficulty in bringing together data from aerial and sea-based sensors near the battlefield. The report found that the Pentagon is “a long way” from its vision of fusing data from the various sensors.

“The communication links, the ability to correlate target tracks by disparate sensors, and the overall information architecture are simply not there,” the report said. “Thus, a Patriot battery on the battlefield can be very much alone.”

Philip Coyle, a former chief Pentagon weapons inspector, said that the lack of information provided to the Patriot batteries is an indication that military commanders do not place a high level of importance on the system’s role in combat. Commanders should provide Patriot operators with information of what aircraft are likely to be flying over the batteries to help avoid friendly fire, he said.

At the same time, the Patriot operators appear to have too much confidence in the system’s ability to choose targets on its own, said Coyle, who currently serves as a senior advisor to the Center for Defense Information, a think tank based here. Despite the need for the Patriot battery to make quick decisions on whether to fire, operators could likely have more input on the decision to do so without adding too much time to the process, he said.

Baker Spring, a senior analyst at the Heritage Foundation, another think tank here, said that he hoped that the fratricide issue could be addressed through modifications to the Patriot system. Spring said that he did not want to downplay the tragedy of the friendly fire accidents, but said he hoped the incidents would not cause the Pentagon to make major changes in future battle planning that could slow the speed of future operations.

While the Patriot system was responsible for several fatalities, it likely saved hundreds of lives during Operation Iraqi Freedom, Spring said.