From Secrecy News:
RISE IN FRATRICIDE SEEN IN THE WAR ON TERROR
Incidents of fratricide in the U.S. war on terrorism increased in recent years, according to a new report (pdf) from the U.S. Army.
"Fratricide" -- the unintended killing or injury of friendly forces -- "is a harsh reality during combat operations," the study states. "Over the course of 2004-2007, the number of fratricide incidents increased, and experts speculate this is due to the high operational tempo and the reliance on technology during the current war."
According to official data, "there were 55 U.S. Army fratricide incidents from 11 September 2001 to 30 March 2008. Forty of these were Class A accidents" -- involving damage costs of $2 million or more and/or destruction of an Army aircraft, missile or spacecraft and/or fatality or permanent total disability -- "resulting in the deaths of 30 U.S. Army personnel."
Human error is a primary causal factor in many fratricide incidents, the study indicated, and "therefore, human error must be considered in the design and development of fratricide countermeasures, including both technical and human-centric solutions... Improved supervision and leadership may have the greatest potential to reduce U.S. fratricide incidents."
See "An Analysis of U.S. Army Fratricide Incidents during the Global War on Terror (11 September 2001 to 31 March 2008)" by Catherine M. Webb and Kate J. Hewett, U.S. Army Aeromedical Research Laboratory, March 2010.