Poor Communication

An American gunship hit a Doctors Without Borders hospital in Kunduz, Afghanistan, last year, killing 42 people.

In major military blunders, rarely is there just one culprit. Human error as well as equipment and procedural failures can add up to devastating consequences. That was the case in the attack on a Doctors Without Borders hospital in Kunduz, Afghanistan.

The problems started when missile fire forced a lumbering AC-130 gunship, sent to eliminate a compound swarming with Taliban fighters, off course. Its targeting systems homed in on an empty field instead.

The crew spotted a collection of buildings that roughly matched the description of the Taliban compound. The gunship’s navigator called an American Special Forces air controller on the ground to seek guidance.

The response was immediate and unequivocal: Open fire.

Location of American commander on the ground Position first indicated by aircraft sensor Intended target 1,080 feet 1,320 feet 1,450 feet Hospital attacked Location of American commander on the ground Position first indicated by aircraft sensor Intended target 1,080 feet 1,320 feet 1,450 feet Hospital attacked Position first indicated by aircraft sensor Intended target 1,080 feet 1,320 feet 1,450 feet Hospital attacked The New York Times | Satellite image by DigitalGlobe via Bing Maps

The air controller was wrong. Even after Doctors Without Borders frantically alerted American commanders that a gunship was attacking the hospital, the airstrike was not immediately called off because the Americans could not confirm that the hospital was free of Taliban fighters.

Sixteen American military personnel, including a general officer, were given administrative punishments for their roles in the strike.

Right Target, Wrong People

A coalition airstrike on Tuesday aimed at Islamic State fighters killed 18 Syrian fighters allied with the United States.

In the fog of war, distinguishing between friend and foe can be perilous. Allies and enemies are commingled on the battlefield. What looks like an insurgent from data gathered from spy satellites or surveillance planes may be a more complicated target.

In the airstrike Tuesday in Tabqah, Syria, Syrian fighters allied with the United States were mistaken for insurgents. Allies on the ground had called in the airstrikes and “identified the target location as an ISIS fighting position,” the Pentagon said, using another name for the Islamic State. But the location turned out to be a position for the Syrian Democratic Forces, who have been fighting the Islamic State alongside the Americans. The military is investigating.

Aleppo Mosul Raqqa Tabqah Location of strike Deir al-Zour ISIS control Homs IRAQ SYRIA By Rebecca Lai, The New York Times | Source: IHS Jane’s (areas of control as of April 4)

Without eyes on the ground, targets can be misleading. Several missiles fired from a C.I.A. drone in March 2011 struck a meeting in northwest Pakistan among locals and Taliban mediators who had gathered to settle a dispute over a chromite mine. While some of the three dozen people killed were Taliban fighters, Pakistani officials said, most were elders or simply residents.

American officials sharply disputed Pakistan's account, saying that all those killed were insurgents. “These people weren't gathering for a bake sale,” an American official said. “They were terrorists.”

Reliance on Local Allies

An American airstrike called in by Iraqi special forces to kill snipers ended up killing as many as 200 Iraqi civilians.

Ideally, American spotters would be able to call in all American airstrikes to help avoid accidentally striking civilians. But in war zones like Iraq and Syria, where small numbers of American Special Operations forces are advising indigenous troops, the advisers must vet and approve information relayed from allied troops closer to the fight. It’s an imperfect arrangement forged in the crucible of combat.

American commanders in Iraq say that an airstrike in Mosul last month that killed scores, if not hundreds, of civilians hit the right target, but that the choice of target relied on partner forces who may not have the same values or standards, especially when it comes to risks to civilians.

Rescue teams work on the debris of a house destroyed by an airstrike that killed more than 100 people in Mosul. Felipe Dana/Associated Press

The top American commander in Iraq, Lt. Gen. Stephen J. Townsend, acknowledged that the airstrike most likely led to the building collapse that killed the civilians. But American officials have also said that the Islamic State may have herded the victims into the building as human shields, or that the attack may have set off a larger blast from explosives set by militants inside the building or nearby.

Maj. Gen. Maan al-Saadi, an Iraqi special forces commander, has said his men called in an airstrike to take out snipers on the roofs of three houses in Mosul. The Iraqi forces, General Saadi said, were unaware that at least some of the houses were filled with civilians.

Nearby Civilians

Two American airstrikes in 2016 and one in 2015 – both in Mosul – killed civilians near designated targets.

Often, civilians stray too close to a target after an American or allied warplane has dropped its weapons, and the pilot is unaware or cannot abort the strike.

In a significant number of the 85 strikes involving civilian casualties that the United States has acknowledged in Iraq and Syria, noncombatants entered the so-called killbox after the weapons were released, according to Airwars, a London-based organization that tracks civilian casualties in war zones.

On Feb. 12, 2016, and again four days later, airstrikes were carried out on Islamic State car-bomb factories in Mosul. American commanders concluded that two civilians were unintentionally killed in each strike when they entered the target area after the munition had been dropped.

American commanders also concluded that an attack on an Islamic State headquarters building in Mosul in 2015 killed four civilians in the building and wounded two others.

Flawed Intelligence

A B-2 bomber mistakenly struck the Chinese Embassy in Belgrade, Serbia, in 1999, killing three people and wounding 20.

American military planners draw on a range of aerial, human and other intelligence to help plot airstrikes, always seeking to prevent civilian deaths. Even so, that planning sometimes goes awry. Most famously, flawed targeting techniques, outdated maps and sloppy follow-up on the ground led to a disastrous result in May 1999.

Satellite-guided bombs from a B-2 bomber struck the Chinese Embassy in Belgrade during the Kosovo War because C.I.A. analysts misidentified the building, and military databases used to catch such mistakes had the wrong address for the embassy. The intelligence failure led to a deadly case of mistaken identity that killed three Chinese and wounded 20.

When the target was initially checked against electronic mapping data in American military and NATO computers to protect against civilian casualties, no red flags were raised because half a dozen government databases listed the old location of the Chinese Embassy, in another part of Belgrade.

A secret document that President Bill Clinton used in authorizing the strike, obtained by The New York Times in 2000, described the Chinese Embassy as a warehouse.