TALL AFAR, Iraq — Buzzing over this northern Iraqi city in her Kiowa scout helicopter, a .50-caliber machine gun and rockets at the ready, Capt. Sarah Piro has proved so skillful in combat missions to support U.S. ground troops that she has earned the nickname Saint.

In recent months of fighting in Tall Afar, Piro, 26, of El Dorado Hills, Calif., has sleuthed out targets, laid down suppressive fire for GIs in battle and chased insurgents through the narrow alleys of this medieval city — maneuvering all the while to avoid being shot out of the sky. In one incident, she limped back to base in a bullet-riddled helicopter, ran to another aircraft and returned to the fight 10 minutes later.

"They call her Saint Piro — she's just that good," said her co-pilot, Chief Warrant Officer Todd Buckhouse, a 19-year Army veteran who has worked with Piro on two tours with the 3rd Armored Cavalry Regiment in Iraq.

"There was no one I wanted to hear more on a raid than her. She's a spectacular Army aviator," said Maj. Chris Kennedy, executive officer of the regiment, which is returning home this month.

Female helicopter pilots such as Piro are demonstrating their valor in Iraq in one of the few direct combat roles women are officially allowed in the military. Their missions often put them at risk of being hit by machine-gun fire and rockets, and require them to shoot back. Piro's unit, Outlaw Troop, lost three of its eight Kiowas when insurgents shot them down over Tall Afar, and four or five others were hit, U.S. officers said. On Piro's first tour in Iraq, her wingman hit a wire and crashed into the Euphrates River. She and Buckhouse made an emergency landing and jumped into the water to try to save the two aviators, but were too late.

Today about 9 percent of women in the Army are aviators, with their numbers having grown since the 1990s. There are four women pilots in Piro's troop of 33 soldiers.

"I didn't want to be a staff officer. I wanted to be an operator," said Capt. Monica Strye, 29, of San Antonio, commander of Outlaw Troop. "I wanted to have more of a combat role."

But female aviators say they still face obstacles from the predominantly male military on the ground. "It's far better than when my mother was in the military, but we still have a long ways to go," said Strye, whose mother was an Army nurse in Vietnam. "I know I constantly have to prove myself."

And even as the 360-degree battlefields of Iraq and Afghan-istan are exposing women to combat as never before, policies excluding women from ground combat units have not been eased, but instead face increased scrutiny in Congress.

Under a law signed in January, the Defense Department must report to Congress on the assignment of women, particularly in the Army, to ensure compliance with existing Pentagon policy, which the law also codified. Before opening any new positions to women, the Defense Department now must tell Congress what justifies the change and observe a 30-day waiting period.

The legislation, while greatly watered down from earlier versions that would have rolled back opportunities for women, still limits the Pentagon's flexibility in adjusting to new wartime realities, critics say. It was passed over the objections of Pentagon leaders.

Congressional critics say the change sends the wrong message to military women, especially the thousands serving in Iraq. Women make up about 15 percent of the active-duty members; 48 women have been killed and more than 350 wounded in Iraq action, the Pentagon says.

At Outlaw Troop's base outside Tall Afar, aircraft come and go around the clock. Piro, Strye and other pilots fly demanding six- to eight-hour missions in full body armor.

One morning last summer, as dawn broke over Tall Afar's labyrinthine Sarai neighborhood, Piro and Buckhouse were watching a building about to be raided. On the ground, assaulting U.S. troops were ambushed from the school. The fire had the GIs pinned down, and medics couldn't evacuate the wounded. "Outlaw, we need a gun run south of the city," came the radio call.

Piro, a graduate of West Point, swooped her Kiowa in from the south to attack with its machine gun. The aircraft was breaking away when it was hit by a barrage of fire. "We're taking fire left," Buckhouse called out. Piro heard the popping of bullets and felt the helicopter lurch. A round had hit the fuel cell, igniting it. An alarm went off in the cockpit.

"We're losing fuel!" Piro said, as the Kiowa started to drop. Flying low and fast, they made it back to the base. When they landed, they saw the fuselage was split. Piro jumped out to prepare another aircraft for flight. Ten minutes later, she and Buckhouse took off for another five to six hours of combat.