— TON - A military investigation into the downing of a Chinook helicopter that killed 30 U.S. service members in Afghanistan found that the mission followed standard operating procedures, Pentagon officials told NBC News on Wednesday.
The investigation found no cause for disciplinary action against any commanders involved in the mission.
The Army Chinook CH-47 helicopter carrying the 30 Americans, including 22 Navy SEALs, was responding to a distress call from a unit of Army Rangers when it was shot down by enemy forces Aug. 6.
The investigation by Central Command found that as the helicopter was attempting to land, a rocket-propelled grenade struck the rear rotor and one of the rotor blades, resulting in a catastrophic explosion. "There was no evidence of a pre-planned ambush," according to a Pentagon press release on an executive summary of the report released late Wednesday.
According to one military official, "It was a standard mission profile, and a bad guy got lucky."
It was the single deadliest incident for coalition forces during the decade-long war. Eight Afghans also were killed in the crash in a remote valley southwest of Kabul.
Military and Defense Department officials also told NBC News that there was nothing unusual about Navy SEALs acting as a quick reaction force to back up the Rangers. "All forces have become interchangeable", according to one source who explained that SEALs will back up Rangers on one mission, Rangers back up SEALs on another.
The results of the investigation are being given to Army and Navy SEAL commands, members of Congress, and family members of those killed. The results are expected to be released later this week.