U.S. and Afghan forces reached the scene 21/2 hours after the attack to provide medical assistance. After 20 minutes more, medevac helicopters began taking the wounded to a hospital in Tarin Kowt, in Oruzgan. More serious cases were later transferred to Kabul.
"They asked us who we were, and we told them we were civilians from Kijran district," said Qudratullah, who lost a leg.
By the U.S. count, 15 or 16 men were killed and 12 people were wounded, including a woman and three children. Elders from the Afghans' home villages said in interviews that 23 had been killed, including two boys, Daoud, 3, and Murtaza, 4.
That evening, Army Gen. Stanley A. McChrystal, then the top U.S. commander in Afghanistan, went to the presidential palace in Kabul to apologize to President Hamid Karzai. Two days later, he went on Afghan television and promised "a thorough investigation to prevent this from happening again."
The Army and the Air Force conducted their own investigations, reaching similar conclusions.
The Army said evidence that the convoy was not a hostile force was "ignored or downplayed by the Predator crew," and the A-Team captain's decision to authorize an airstrike was based on a misreading of the threat when, in fact, "there was no urgent need to engage the vehicles."
The Air Force concluded that confusion over whether children were present was a "causal factor" in the decision to attack and, in an internal document last year, said drone crews had not been trained to notice the subtle differences between combatants and suspicious persons who may appear to be combatants.
The military has taken some steps to address these problems. Screeners now have access to radio traffic, so if a drone pilot makes a mistake, the screeners can correct it. Drone crews and screeners are now trained to use more precise descriptions in radio transmissions. And, shortly after the incident, McChrystal banned the use of the term "military age male," saying it implied that every adult man was a combatant.
Some officers in the Pentagon drew another lesson from the incident: An abundance of surveillance information can lead to misplaced confidence in the ability to tell friend from foe.
"Technology can occasionally give you a false sense of security that you can see everything, that you can hear everything, that you know everything," said Air Force Maj. Gen. James O. Poss, who oversaw the Air Force investigation. "I really do think we have learned from this."
McChrystal issued letters of reprimand to four senior and two junior officers in Afghanistan. The Air Force said the Predator crew was also disciplined, but it did not specify the punishment. No one faced court-martial, the Pentagon said.
Several weeks after the attack, American officers travelled to the villages to apologize to survivors and the victims' families.
They gave each survivor 140,000 afghanis, or about $2,900.
Families of the dead received $4,800.
Times staff writer Laura King and special correspondent Aimal Yaqubi in Kabul contributed to this report.
(BEGIN TEXT OF INFOBOX)
The Predator is a medium-altitude, propeller-driven drone used for surveillance and attacks on ground targets. The 27-foot- long craft is flown remotely by a pilot at a ground station and can remain aloft for as long as 24 hours at a maximum altitude of 25,000 feet.
It is equipped with multiple cameras, including an infrared device that enables it to produce live video at night. The aircraft can carry two Hellfire missiles. A more heavily armed version, the MQ-9 Reaper, can carry satellite-guided bombs and four missiles.
The Air Force has 165 Predators and 70 Reapers, with 130 deployed to Afghanistan and other overseas locations. The Central Intelligence Agency has an unknown number of Predators and Reapers in use over Pakistan and other places, according to counter-terrorism officials.
CIA-controlled drones are estimated to have killed more than 180 suspected militants in Pakistan since President Obama took office. Some human rights advocates have condemned those attacks as extrajudicial killings.
U.S. Air Force drones in Afghanistan carry out conventional military operations, providing air cover and surveillance for American and allied ground troops.
-- David S. Cloud
About this story
Times staff writer David S. Cloud, who covers the Pentagon, reported from Washington. Laura King, Times bureau chief in Kabul, along with special correspondent Aimal Yaqubi in Afghanistan, located and interviewed survivors. Except where indicated, all quotations attributed to the Predator drone crew in Nevada, the AC-130 crew flying over Afghanistan and the Army special operations soldiers on the ground were drawn from the official transcript, which was obtained through a Freedom of Information Act request.