A helicopter crash in eastern Afghanistan which killed nearly 40 Afghan and U.S. service members in August was caused by an insurgent-fired rocket-propelled grenade (RPG), according to a U.S. report.

Standing by on a hilltop, soldiers with the 101st Division Special Troops Battalion, 101st Airborne Division watch as two Chinook helicopters fly in to take them back to Bagram Airfield, Afghanistan. (Photo by Spc. Mary L. Gonzalez, US Army)
The accident involving a CH-47 Chinook helicopter happened on August 6 in the Tangi Valley of Wardak Province, killing 30 U.S. and 8 Afghan service members as well as one U.S. military dog. The incident represented the highest number of U.S. forces killed during a single event since the U.S.-led war began in late 2001.
A report released by U.S. Central Command on Thursday confirmed the crash was caused by an insurgent-fired rocket-propelled grenade which struck the CH-47’s aft rotor-blade as the aircraft approached its landing zone. The investigation found no evidence of a pre-planned ambush.
The investigation determined that the helicopter’s mission and tactics were consistent with previous missions, and that the forces and capabilities selected to execute the mission were appropriate given the agility required to maintain pressure on insurgent networks.
It further concluded that the Army aviators flying the mission were fully qualified to perform their required tasks, that the CH-47 helicopter involved was fully mission capable, and that the number of personnel on board was tactically sound and well within the helicopter’s technical specifications and capabilities.
“This report reinforces my appreciation and unbounded admiration for the courage and skill continuously shown by our Special Operations Forces, conventional forces, and our partner forces from the Government of the Islamic Republic of Afghanistan,” said U.S. Central Command Commander General James Mattis. “I offer my deepest condolences to the families and friends of the fallen during a mission made in defense of both our nations.”
He added: “The ultimate sacrifice of the fallen, and the enduring loss and sacrifice of their loved ones, will be remembered by all of us who take this loss as a reason to focus even more strongly on our mission.”
Days after the crash, on August 9, the Taliban insurgent who allegedly fired the RPG was killed as a result of a NATO airstrike in the Chak district of Wardak province. The same airstrike also killed a local Taliban leader identified as Mullah Mohibullah.