By Bradley Graham
Washington Post Staff Writer
Sunday, December 19, 2004; Page A31

AL UDEID AIR BASE, Qatar -- A giant video screen, hung inside a warehouse here that has been transformed by the U.S. Air Force into a state-of-the-art operations center, provides a window on the military action that still occupies the skies over Iraq.

One day earlier this month, the radar signatures of a half-dozen U.S. fighter jets could be seen over Mosul, Fallujah and Babil Province south of Baghdad, their locations reflecting the best guesses of military commanders about where trouble might flare.

The morning and early afternoon passed without incident, but the quiet was suddenly broken at 3:14 p.m. when soldiers in Mosul reported taking small arms fire.

Nothing gets higher priority for military planes involved in the Iraq mission than a situation of troops under attack. Within seconds of the alert, a yellow box with "TIC" -- for Troops in Contact -- popped up on the video map. The Navy fighter jets that had been over Mosul swooped low in a show of force, and the attackers faded away, forestalling more aggressive measures by the aircraft.

Such action and reaction have become the norm for the air war, a part of the conflict in Iraq that is largely overshadowed by the grittier and often bloodier efforts of forces on the ground to battle an elusive and determined insurgency.

In contrast to the opening days of the invasion of Iraq 21 months ago, when U.S. warplanes struck a series of planned targets in a display that some in the Pentagon dubbed "shock and awe," the air campaign has become more ad hoc and less showy.

Pilots now take their cues for missions not from Air Force strategists but from Army and Marine commanders who daily submit requests for where they think aircraft can help most in support of ground operations. Instead of taking to the air with a clear idea of what they will strike and when, the pilots now largely wait for something to happen -- an attack on U.S. forces, for instance, or the discovery of militants ensconced somewhere -- and then fly into action.

With the exception of large offensive ground operations, such as the assault on Fallujah last month, days can pass without a bomb being dropped. This has led to the use of U.S. combat aircraft in nontraditional ways.

Fighters, for instance, now often are employed as surveillance and reconnaissance platforms. Using video and infrared cameras on their airframes, they cruise above oil pipelines and power plants, scouting for evidence of attack damage or suspicious activity.

When an opportunity for an airstrike presents itself, the weapon of choice may be nontraditional, particularly if the desire is for a relatively small missile and a quick attack. Predator drones are a case in point. Built originally as spying platforms to linger high above targets, they are being used occasionally as shooters in Iraq, firing Hellfire missiles.

In all, more than 500 U.S. and other coalition aircraft remain on duty in Central Command's area of responsibility, which covers not just Iraq but also Afghanistan and the Horn of Africa. More than a fourth of these are jet fighters -- Air Force F-15s , F-16s and A-10s, Navy F-14s and F/A-18s, Marine AV-8s and F/A-18s and British GR-4s and GR-7s.

At night, these strike aircraft are joined by slower moving but particularly lethal AC-130 gunships. Operated by Special Operations forces, these propeller-driven planes can pour down withering fire from any of three weapons that poke from their left side -- a 25mm Gatling gun, a 40mm cannon or a 105mm howitzer.

An additional 55 or so aircraft are for gathering intelligence. These include a Global Hawk drone and a small fleet of Predators, as well as high-flying U-2s, signals-scanning RC-135s and ground-spying E-8Cs. Rounding out the air forces are dozens of service planes, including KC-135 fuel tankers and C-130 transport aircraft.

At any given time, the skies over Iraq contain, in the words of one senior officer here, "a cocktail of weapons" -- from 2,000-pound bombs to 100-pound Hellfire missiles -- waiting to be let loose should the need arise. But the biggest recent advance in the air arsenal came in September, officers said, with the debut of a satellite-guided, 500-pound bomb designated the GBU-38.

The new munition, smaller than older 1,000-pound and 2,000-pound models, can still do serious damage to a building but with less risk of collateral harm to neighboring structures, officers said. Guided by Global Positioning System satellites, the bomb also has the advantage of being able to operate through cloud cover, unlike a laser-directed version, the GBU-12.

Figuring out which planes should fly where and perform what mission is the work of the Combined Air Operations Center (CAOC) here at Al Udeid Air Base, in the desert outside Doha, Qatar, about 700 miles southeast of Baghdad. Established three years ago initially as a backup for a U.S. operations center at Prince Sultan Air Base in Saudi Arabia, this facility took over as the main air command post in the summer of 2003 after the United States decided to close the one in Saudi Arabia.

In an interview, Lt. Gen. Walter E. Buchanan III, the top commander of air operations for the U.S. Central Command, recalled the original rushed, makeshift effort to set up an air center here. It was prompted, he said, by concern about two possibilities: that an attack on the facility at Prince Sultan Air Base could leave it disabled; or that the Saudis would decide not to let the United States use the facility in connection with an invasion of Iraq.

"At that point, we cleared out this warehouse and laid out tables and wired computers together as best we could," Buchanan said.

The Saudis eventually allowed use of Prince Sultan Air Base -- and two other bases -- during the invasion. But U.S. authorities decided to cease air operations in Saudi Arabia afterward to demonstrate, Buchanan said, that the United States can keep to its commitments to pull forces out of Middle East nations.

"We wanted to hold true to our word that we would in fact leave, because there are people in this region who have quietly told us that if they let us in, we'd never leave," the general said.

Reluctant to publicize the existence of the CAOC on their soil, the Qataris until recently had blocked journalists from visiting the facility. But permission was granted to The Washington Post for a reporting visit this month.

Today, the center is a hive of activity. A large operations room features rows of desktop computers manned by officers responsible for every aspect of a flight. The chief operations officer, seated on a raised platform in the middle of the room, is flanked by an intelligence specialist. A legal expert is nearby, as are representatives of the Army and Marines to facilitate coordination with ground units.

The loud hum of an industrial air conditioner drowns out much other noise, but most communications are transmitted not by voice but on a computer chat network known as "mIRC," for multi-user Internet Relay Chat. The system enables officers with secret clearances here and elsewhere around the world to select various windows -- air operations, intel, search and rescue, and so on -- and watch events unfold in terse one- or two-line text messages.

Off the operations room, in the back of the cavernous building and in a suite of offices on a second floor, other military personnel labor round the clock drafting aircraft assignments. Each day, the military command in Baghdad submits a list of "air support requests," indicating which missions are the most important and what kind of support is required: air cover for upcoming raids, protection for truck convoys, patrols over oil pipelines, reconnaissance of suspected safe houses.

From receipt of the requests to completion of a day's Master Air Attack Plan, the process takes about 44 hours, which officers here say is quick by historical standards.

For air planners accustomed traditionally to plotting their air campaigns, the idea of letting ground commanders take the lead in shaping flight operations has taken some getting used to.

"The ground guys are doing the prioritizing, we're not," said Navy Cmdr. Todd Kiefer, a liaison officer. "That's a big difference."

CAOC staffers still reserve for themselves the decision on which aircraft to assign, and they try to encourage ground commanders to specify only desired effects, not exact types of planes or munitions. Still, the ground commanders cannot resist expressing favorites.

"They'll say they want an AC-130 overhead. We'll say: Do you really need that, or just something that can kill bad guys?" said Air Force Maj. Steve Herman, who works in the strategy section. "We'll go back and forth. We'll say: 'Don't tell us you need a specific platform; tell us the effect you want.' "

Col. Rex Snider, the senior intelligence officer in the CAOC, estimated that 60 to 70 percent of targets requested for airstrikes have tended to come from Special Operations forces. He and other officers here stressed the care that is taken in assessing the potential for civilian casualties and unintended property damage before authorizing a strike, although official records show that misses still occur.

In the case of the Fallujah operation, for instance, Buchanan cited statistics showing that 28 satellite-guided bombs dropped by Air Force and Navy planes scored a "hit rate" of 89 percent; the rate for 35 laser-guided GBU-12s was 91 percent. A hit, Buchanan said, was when a weapon landed exactly where intended and exploded.

Marine aircraft dropped the large majority of bombs in Fallujah, but Buchanan said he did not have Marine Corps hit rates, and a spokesman in Iraq was unable to produce them.

During the invasion of Iraq, the U.S. military ran air operations from more than a dozen bases in the Persian Gulf region. In the past year, it has stopped using more than half of those and sought to consolidate at what Buchanan called several "enduring" bases, including Al Dhafra in the United Arab Emirates, Ali Al Salem in Kuwait and Al Udeid here.

As a sign that a long-term presence in Qatar is planned, a 104,000-square-foot CAOC made of concrete is under construction here along with a set of flight-line support facilities. The Qataris are paying more than half the estimated $500 million bill for the project.