Friendly fire is an attack by a military force on non-enemy, own, allied or neutral, forces while attempting to attack the enemy, either by misidentifying the target as hostile, or due to errors or inaccuracy. Fire not intended to attack the enemy, such as negligent discharge and deliberate firing on one's own troops for disciplinary reasons, is not called friendly fire. Nor is unintentional harm to non-combatants or structures, which is sometimes referred to as collateral damage. Training accidents and bloodless incidents also do not qualify as friendly fire in terms of casualty reporting.
Use of the term "friendly" in a military context for allied personnel or materiel dates from the First World War, often for shells falling short. The term friendly fire was originally adopted by the United States military. Many North Atlantic Treaty Organization (NATO) militaries refer to these incidents as blue on blue, which derives from military exercises where NATO forces were identified by blue pennants and units representing Warsaw Pact forces by orange pennants. Whereas in classical forms of warfare, including hand-to-hand combat death from a "friendly" was rare, in industrialized warfare, deaths from friendly fire are common.
Paul R. Syms argues that fratricide is an ancient phenomenon He goes on to note recorded events in Ancient Greece and other early accounts of battles. He and other historians note that weapons such as guns, artillery, and aircraft dramatically increased friendly-fire casualties.
By the 20th and 21st centuries, friendly-fire casualties have likely become a significant percentage of combat injuries and fatalities. Jon Krakauer provides an overview of American casualties during and since the Second World War:
According to the most comprehensive survey of casualties (both fatal and nonfatal), 21 percent of the casualties in World War II were attributable to friendly fire, 39 percent of the casualties in Vietnam, and 52 percent of the casualties in the first Gulf War. Thus far in the ongoing conflicts in Iraq and Afghanistan, casualty rates are 41 percent and 13 percent, respectively.
In the annals of warfare, deaths at the hand of the enemy are often valorized, while those at that hand of friendly forces may be cast in shame. Moreover, because public relations and morale are important, especially in modern warfare, militaries may be inclined to under-report friendly-fire, especially when they are in charge of both investigations and press releases:
If fratricide is an untoward but inevitable aspect of warfare, so, too, is the tendency by military commanders to sweep such tragedies under the rug. It's part of a larger pattern: the temptation among generals and politicians to control how the press portrays their military campaigns, which all too often leads them to misrepresent the truth in order to bolster public support for the war of the moment."
Although there may well be a longstanding history of such bias, Jon Krakauer claims "the scale and sophistication of these recent propaganda efforts, and the unabashedness of their executors" in Iraq and Afghanistan is new.
Friendly fire arises from the "fog of war" – the confusion inherent in warfare. Friendly fire that is the result of apparent recklessness or incompetence may be improperly lumped into this category. The concept of a fog of war has come under considerable criticism, as it can be used as an excuse for poor planning, weak or compromised intelligence and incompetent command.
Errors of position occur when fire aimed at enemy forces may accidentally end up hitting one's own. Such incidents are exacerbated by close proximity of combatants and were relatively common during the First and Second World Wars, where troops fought in close combat and targeting was relatively inaccurate. As the accuracy of weapons improved, this class of incident has become less common but still occurs.
Errors of identification happen when friendly troops are mistakenly attacked in the belief that they are the enemy. Highly mobile battles, and battles involving troops from many nations are more likely to cause this kind of incident as evidenced by incidents in the 1991 Gulf War, or the shooting down of a British aircraft by a U.S. Patriot battery during the 2003 invasion of Iraq. In the Tarnak Farm incident, four Canadian soldiers were killed and eight others injured when a U.S. Air National Guard Major dropped a 500 lb (230 kg) bomb from his F-16 onto the Princess Patricia's Canadian Light Infantry regiment which was conducting a night firing exercise near Kandahar. Another case of such an accident was the death of Pat Tillman in Afghanistan, although the exact circumstances of that incident are yet to be definitively determined.
During World War II, "invasion stripes" were painted on Allied aircraft to assist identification in preparation for the invasion of Normandy. Similar markings had been used when the Hawker Typhoon was first introduced into use as it was otherwise very similar in profile to a German aircraft. Late in the war the "protection squadron" that covered the elite German jet fighter squadron as it landed or took off were brightly painted to distinguish them from raiding Allied fighters.
Errors of response inhibition have recently been proposed as another potential cause of some friendly fire accidents. These types of errors are different from visual misidentification, and instead appear to be caused by a failure to inhibit a shooting response.
A number of situations can lead to or exacerbate the risk of friendly fire. Difficult terrain and visibility are major factors. Soldiers fighting on unfamiliar ground can become disoriented more easily than on familiar terrain. The direction from which enemy fire comes may not be easy to identify, and poor weather conditions and combat stress may add to the confusion, especially if fire is exchanged. Accurate navigation and fire discipline are vital. In high-risk situations, leaders need to ensure units are properly informed of the location of friendly units and must issue clear, unambiguous orders, but they must also react correctly to responses from soldiers who are capable of using their own judgement. Miscommunication can be deadly. Radios, field telephones, and signalling systems can be used to address the problem, but when these systems are used to co-ordinate multiple forces such as ground troops and aircraft, their breakdown can dramatically increase the risk of friendly fire. When allied troops are operating the situation is even more complex, especially with language barriers to overcome.
Some analyses dismiss the material impact of friendly fire, by concluding friendly-fire casualties are usually too few to affect the outcome of a battle. The effects of friendly fire, however, are not just material. Troops expect to be targeted by the enemy, but being hit by their own forces has a huge negative impact on morale. Forces doubt the competence of their command, and its prevalence makes commanders more cautious in the field.
Attempts to reduce this effect by military leaders involve identifying the causes of friendly fire and overcoming repetition of the incident through training, tactics and technology.
Most militaries use extensive training to ensure troop safety as part of normal co-ordination and planning, but are not always exposed to possible friendly-fire situations to ensure they are aware of situations where the risk is high. Difficult terrain and bad weather cannot be controlled, but soldiers must be trained to operate effectively in these conditions, as well as trained to fight at night. Such simulated training is now commonplace for soldiers worldwide. Avoiding friendly fire can be as straightforward as ensuring fire discipline is instilled in troops, so that they fire and cease firing when they are told to. Firing ranges now also include 'Don't Fire' targets.
The increasing sophistication of weaponry, and the tactics employed against American forces to deliberately confuse them has meant that while overall casualties have fallen for American soldiers in the late 20th and 21st centuries, the overall percentage of deaths due to friendly fire in American actions has risen dramatically. In the 1991 Gulf War, most of the Americans killed by their own forces were crew members of armored vehicles hit by anti-tank rounds. The response in training includes recognition training for Apache helicopter crews to help them distinguish American tanks and armored vehicles at night and in bad weather from those of the enemy. In addition, tank gunners must watch for "friendly" robotic tanks that pop out on training courses in California's Mojave Desert. They also study video footage to help them recognize American forces in battle more quickly.
Improved technology to assist in identifying friendly forces is also an ongoing response to friendly fire problems. From the earliest days of warfare, identification systems were visual and developed into extremely elaborate suits of armour with distinctive heraldic patterns. When radar was developed during World War II, IFF systems to identify aircraft developed into a multitude of radio beacons.
Correct navigation is vital to ensuring units know where they are in relation to their own force and the enemy. Efforts to provide accurate compasses inside metal boxes in tanks and trucks has proven difficult, with GPS a major breakthrough. Government contractors are rushing to perfect infra-red and carbon dioxide laser beacons that can be mounted on armored vehicles and that will identify themselves to their own forces.
Other technological changes include hand-held navigational devices that use satellite signals, giving ground forces the exact location of enemy forces as well as their own. The use of infra-red lights and thermal tape that are invisible to observers without night-goggles, or fibres and dyes that reflect only specific wavelengths are still in their infancy, but may prove to be key identifiers for friendly infantry units at night.
There is also some development of remote sensors to detect enemy vehicles – the Remotely Monitored Battlefield Sensor System (REMBASS) uses a combination of acoustic, seismic vibration, and infrared to not just detect, but identify vehicles.
Some tactics make friendly fire virtually inevitable, such as the practice of dropping barrages of mortars on enemy machine gun posts in the final moments before capture. This practice continued throughout the 20th century since machine guns were first used in World War I, and the high friendly fire risk has generally been accepted by troops since machine gun emplacements are tactically so valuable, and at the same time so dangerous that the attackers wanted them to be shelled, considering the shells far less deadly than the machine guns. Tactical adjustments include the use of "kill boxes", or zones that are placed off-limits to ground forces while allied aircraft attack targets, which goes back to the beginning of military aircraft in World War I.
The shock and awe battle tactics adopted by the American military – overwhelming power, battlefield awareness, dominant maneuvers, and spectacular displays of force – are employed because they are believed to be the best way to win a war quickly and decisively, reducing casualties on both sides. However, if the only people doing the shooting are American, then a high percentage of total casualties are bound to be the result of friendly fire, blunting the effectiveness of the shock and awe tactic. It is probably the fact that friendly fire has proven to be the only fundamental weakness of the tactics that has caused the American military to take significant steps to overturn a blasé attitude to friendly fire and assess ways to eliminate it.
This list shows friendly fire incidents committed by combatants against friendly combatants and prisoners throughout history. These incidents range from the killing of Royalist commander, the Earl of Kingston, by Royalist cannon fire during the English Civil War, the bombing of American troops by Eighth Air Force bombers during Operation Cobra in World War II, the eight-hour firefight between British units during the Cyprus Emergency, the downing of a British helicopter by a British warship during the Falkland War, the shooting of two U.S. Army Black Hawk helicopters by USAF fighters in 1994 during the Iraqi no-fly zones, and the killing of a Royal Military Policeman by a British sniper during the war in Afghanistan.