The only movement comes from two US Black Hawk helicopters sweeping low on a reconnaisance mission.

For the four pilots, the scene appears tranquil. But tensions are high, with the flights coming less than 24 hours after Iraqi small arms fire shot down another Black Hawk close by, killing up to seven soldiers.

The area around Karbala, one of two holy Shiite Muslim cities in central Iraq, was the scene of heavy fighting between the US 3rd Infantry Division and forces loyal to Iraqi President Saddam Hussein this week.

Although the infantry soldiers broke away from the city to launch their lightning push towards Baghdad on Wednesday, leaving seemingly little resistance, the Black Hawk crash highlighted for pilots the threats that still exist in Karbala and elsewhere.

"The biggest danger is the guy still loyal to Saddam who has decided he is going to take a pot shot with an AK-47 or an old hunting rifle," Black Hawk pilot Eric Strecker told AFP just before Thursday's flight.

"Also they (Saddam loyalists) have handed out SAM7s and other hand portable missiles, they would be another big threat."

The Black Hawks, like most of the US military's helicopters, are sophisticated aircraft but are particularly vulnerable to small arms fire.

This was highlighted when, according to the Pentagon, seven people were killed when a Black Hawk was downed by small arms fire near Karbala on Wednesday night.

Strecker flew in what became an urban warfare nightmare for US pilots in Somalia in the early 1990s, when local fighters shot down a Black Hawk in Mogadishu after what should have been a relatively straightforward US search and capture mission went badly wrong.

But by the end of the exercise, 18 Americans were killed, hundreds of Somalis lost their lives and thousands were injured. The incident was featured in last year's Hollywood blockbuster "Black Hawk Down."

Strecker warned there could be further helicopter casualties in the battle for Iraq in similar forms of combat.

This is a particular concern because although the infantry troops have pushed into the outskirts of Baghdad, many of the cities left in their wake to the south, such as Karbala, Najaf and Nasariyah, still contain fierce pockets of resistance.

"It could take as little as one round or lots of rounds (to bring a Black Hawk down). It all depends on what they shoot," he said.

"If two shots hit both pilots, that's it."

However Strecker stressed that Black Hawks, which are used on a wide variety of missions, including combat support, special operations and medivacs, could still fly home after taking heavy punishment.

"If a round hits the right spot, I've seen helicopters take 30 or 40 rounds and nobody even knows it."

Strecker's co-pilot on Thursday was Katrina Lewison, a 25-year-old who has been flying for less than three years.

She said Wednesday's crash brought home to her the realities of flying in what are still potentially very hostile areas.

"Considering that the Black Hawk was shot down close to Karbala, it sends flags up that you are going close to enemy territory," Lewison said after the flight.

Despite Strecker and Lewison's concerns, Thursday's flight went ahead smoothly, with the few farmers and other people seen below in the spread out villages south of Karbala offering nothing more dangerous than a bemused stare upwards, with a few even offering an occasional wave.

SPACE.WIRE