The crash on landing in May 2011 in a remote part of Panjwaii district destroyed the $45-million Chinook and left eight others with minor injuries, according to the report released Friday.
The incident occurred as the pilot attempted to land the packed helicopter by moonlight on a dry river bed and, according to the report, "inadvertently" caused the aircraft to drift to the right as it landed in an intense dustball.
"The investigation concluded that the use of inadequate landing procedures in a degraded visual environment resulted in the helicopter landing with right drift, causing it to dynamically roll over," the report states.
The chopper carrying 26 passengers and five crew — one of two ferrying troops to the mission — hit the ground hard, made a horrifying sound as it rolled onto its side, and pitched soldiers and equipment around the darkened interior.
Some soldiers and a Canadian Press reporter aboard were initially trapped as the smell of fuel filled the cabin, but a crew member was able to douse flames in one engine.
Passengers were "piled up on top of one another," making getting out in a hurry difficult but everyone was able to exit safely, the report states.
One man's piercing screams filled the air, and a few soldiers were flown to a military hospital in Germany.
"I still treat my wounds of that day, which will remain etched in my memory," one soldier, who asked not to be named, has previously told The Canadian Press.
"I have some friends who will never come back to work."
In comments accompanying the report, the director of flight safety Col. Steve Charpentier notes the challenges of flying helicopters in difficult environments.
It's one reason, he says, clear and detailed procedures need to be in place.
"Even though we had an accident and lost an aircraft, luck was indeed on our side," Charpentier writes.
"Every occupant survived and was able to tell their story."
Most of those aboard — in full combat gear — were not wearing seat belts, but the report says military brass accepted the calculated risk.
"As the mission was part of a deliberate operation, the passengers all wore ballistic vests, helmets and rucksacks as they sat in their seats, with the majority not wearing seatbelts," the report says.
"All injuries sustained...were caused by falling on the aircraft structure, being hit by loose objects, falling on other occupants and/or having other occupants fall on them," the report says.
The report did suggest flying procedures were "not clear" in that they did not mandate an altitude at which the pilots should have aborted the landing when they lost visibility.
Rotor-driven dust "brownouts" in Afghanistan posed a serious hazard for chopper pilots. In July 2009, for example, a Canadian Forces Griffon leaving a forward operating base whipped up blinding dust, clipped a wall, flipped, and burst into flames. Three soldiers were killed.
It's not clear why the military took four years to release the report, but the former chief investigator for the flight-safety directorate at one point blamed a lack of resources.
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