The night Iraqi tanks stormed into the Saudi border town of Khafji, Marine 1st Lt. D. Grant Olbrich was flying his OV-10 reconnaissance plane, watching flashes of light from below.

He was flying tandem with another Marine who, from the back seat, picked out targets and coordinated air strikes with land-based Marines at the southern outskirts of the town."I remember these puffs of smoke and just saying, `Hey, Jonesey, look at this,' " said Lt. Olbrich, whom everyone calls Homer.

"Then I realized (the smoke) wasn't artillery pieces we were hitting, but triple-A (anti-aircraft artillery) fire. I saw these tracers coming up and going above us." It was terrifying, he said.

For the 27-year-old pilot, it was his first combat sortie since his unit, Marine Attack Squadron 231, relocated from North Carolina to this makeshift air base in late December.

It was the kind of mission that combat pilots here look back on as confidence builders, especially now that they are gearing up for close air-support missions to add more firepower to Marine ground or beach assaults into Kuwait.

Many recall the intensity of that Iraqi artillery and missile fire, much of which has subsided in the past two weeks. The pilots speculate that Iraq is saving ammunition to try to repulse an all-out allied thrust into Kuwait and probably has imposed strict "fire discipline" to make sure every artillery burst is likely to score a direct hit.

"They have a pretty good integrated air defense," said Capt. Madison "Cookie" Crum. "They're too smart to just shoot wildly, although the lack of hits has more to do with the skills of our pilots.

"Sometime you see them shoot only after the bombs have gone off and the planes are out of there," he said. "Their fire discipline had impressed me, though. They shoot when they think they have you. You can't just write them off after dropping your bombs."

Capt. Bill Delaney, 29, of Brookeville, Md., described his first encounter with anti-aircraft fire. "It seems almost harmless. There are these little puffs of blue smoke; you can't see the muzzle flash. Sometimes you can't even see the smoke."

Delaney, who flies an AV-8B Harrier jet mostly in daylight, added: "Then you kind of realize there's somebody down there shooting at you. It does sort of remind you this is not a game. It's serious."