ADDS DATE OF CRASH - FILE - A US Marine tries to take cover, perched on a container, trying to shelter from the dust as a Chinook helicopter arrives to pick up supplies at Forward Operating Base Edi in the Helmand Province of southern Afghanistan, in this June 9, 2011 file photo. Afghan President Hamid Karzai says 31 U.S. special forces and seven Afghan soldiers were killed when a helicopter, similar to the one shown crashed in eastern Wardak province Saturday Aug. 6, 2011. (AP Photo/Anja Niedringhaus, File)

Associated Press
ADDS DATE OF CRASH - FILE - A US Marine tries to take cover, perched on a container, trying to shelter from the dust as a Chinook helicopter arrives to pick up supplies at Forward Operating Base Edi in the Helmand Province of southern Afghanistan, in this June 9, 2011 file photo. Afghan President Hamid Karzai says 31 U.S. special forces and seven Afghan soldiers were killed when a helicopter, similar to the one shown crashed in eastern Wardak province Saturday Aug. 6, 2011.  (AP Photo/Anja Niedringhaus, File)
ADDS DATE OF CRASH - FILE - A US Marine tries to take cover, perched on a container, trying to shelter from the dust as a Chinook helicopter arrives to pick up supplies at Forward Operating Base Edi in the Helmand Province of southern Afghanistan, in this June 9, 2011 file photo. Afghan President Hamid Karzai says 31 U.S. special forces and seven Afghan soldiers were killed when a helicopter, similar to the one shown crashed in eastern Wardak province Saturday Aug. 6, 2011. (AP Photo/Anja Niedringhaus, File)
View Comments (50)