KANDAHAR, Afghanistan — With air strikes and helicopter strafing being blamed for the mounting civilian death toll in Afghanistan, Canadian air crews say they don't intend to add to the gruesome statistics.

"They've been trained in a high degree to use of the rules of engagement," said Col. Christopher Coates, the commanding officer of the Canadian Air Wing in Kandahar.

Long a source of friction between Afghan President Hamid Karzai's government and NATO forces, civilian deaths became a particular focus during U.S. envoy Richard Holbrooke's first visit to Afghanistan over the weekend.

The United Nations estimates that 2,100 civilians were killed in 2008 - a 40 per cent increase over the previous year's estimate. NATO disputes the number, saying it believes only 1,000 innocent bystanders were killed last year. In either case, it's unclear how many may have been insurgents.

But in any event, Holbrooke and Karzai signed a declaration Sunday aimed at ensuring closer co-operation between the U.S. and Afghanistan in order to reduce the carnage.

For their part, Canadian troops have been responsible for a handful of civilian deaths in Kandahar since the first battle group deployed for the current mission in early 2006. They were street-level shootings, mostly involving motorists who refused to heed warnings to stop.

But overall, the vast majority of innocent civilian deaths have come from aircraft bombings and attack helicopter gunfire as overwhelmed NATO ground troops do battle with Taliban fighters who think nothing of taking cover among civilians.

Canada's six CH-47D Chinook transport helicopters, deployed to ferry troops and supplies, come armed with three heavy-calibre machine guns for self-defence.

Also in theatre are eight CH-146 Griffon utility helicopters, specially outfitted with weapons that include, in some cases, a six-barrelled automatic Gatling-type gun, known as an M134D.

The Griffons are meant to serve as escorts for the lumbering Chinooks, but will also provide overhead security for ground convoys to prevent ambush by insurgents.

Unlike the American AH-64 Apache attack helicopters, the Canadian aircraft will have a strictly defensive role, firing only when they or their consorts were fired upon, Lt.-Gen. Angus Watt, chief of the air staff, said in an interview with The Canadian Press.

Still, the preparations for those unexpected and potentially messy ambushes has focused the attention of the flight crews as they've trained in the desert these last several weeks - especially the gun crews.

"They've honed their marksmanship - or their weapons handling skill,"said Coates, a 21-year veteran helicopter pilot.

The gunners, who will fly missions on both the Chinooks and Griffons depending on schedule, know their jobs and have a set of instructions and directives that must be followed, he added.

"As well, in theatre they've really got their crew co-operation down."

Crew co-operation is vital in those split-second moments when a gunner must decide whether the target in his sights is an insurgent or an innocent bystander.

It's the same sort of awful decision soldiers on the ground have faced over the past three years. Now, gunners like Master Cpl. Al Gorrie find themselves wrestling with the same such do-or-die moments while in a helicopter that's whipping over barren grape fields and mountain passes.

"Once you get the hang of it, it's just (that) tracking the target differs when you and the target are moving," said the 28-year-old reservist from Hamilton, Ont.

"In training we've prepared for incidents in varying circumstances. We're training to take into account a lot of things: the enemy, the locals in the area and trying to minimize the damage around that area."

Thoughts of what might happen - being ambushed and having to return fire or taking ground fire in a landing zone - are shoved to the back of his mind every time he climbs aboard the aircraft, Gorrie said.

But that doesn't mean they go away.

"Are you aware of the danger?" he said. "Always."