At Ourches, the 12th joined the 1st Aero Squadron and began active operations over the front.
It was equipped with SPAD S.XIA.2s aircraft.
In combat, the mission of the 12th Aero Squadron was general surveillance of the enemy rear areas by means of both visual and photographic reconnaissance.
These missions were carried out for the purpose of intelligence-gathering and informing First Army headquarters informed of enemy movements and preparations for attacks or retreats of its infantry forces.
The 12th identified enemy activity along roads and railroads, ground stations, various storage dumps and airfields; the numbers of fires and activities of enemy aircraft, and the amount of anti-aircraft artillery was also monitored and reported.
Due to the nature of the missions and the depths of enemy area which was penetrated, the missions were carried out at high altitudes, usually between 4,500 and 5,500 meters.

With few exceptions, the 12th’s pilots had never flown combat, but most of the observers had spent a number of weeks flying with French squadrons on active missions.
One of these, Lieutenant Stephen W. Thompson, was at the 1st Squadron Gunnery School at Cazaux Airdrome, near Bordeaux when he was loaned on 5 February to the 123d French Breguet Squadron due to a shortage of observers in that unit.
Returning from a bombing raid on Saarbruken, the aircraft in which Lt Thompson was operating the rear guns was attacked by German Albatross pursuit ships.
He shot one down, becoming the first man in an American uniform to shoot down an enemy airplane.
Later, on 28 July 1918, as a member of the 12th, he was credited with two more "kills."

The 12th’s operations in the Toul Sector was a seasoning period for the squadron as it gained experience over a relatively inactive front with almost no enemy air opposition. "
On the other hand," according to an Air Service report after the war, "the enemy antiaircraft fire in the sector was exceedingly dense, active and accurate.
Pilots of the Group were adept at evading antiaircraft fire after a month in the sector."
On 10 June, the 12th Aero Squadron moved to the Baccarat Sector and to the unfinished Flin Aerodrome, from which they supported the 42d American and 167th French Divisions.
There, the 12th began to receive the latest in French observation aircraft, the Salmson 2A2.
This front, too, was considered "stabilized" or quiet, but the opposing German air force, while not flying the latest types, was active and aggressive.
The 12th flew visual and photographic reconnaissance, adjusted artillery fire, and staged "infantry-contact patrols" to locate the front lines.
At Ourches, the 12th joined the 1st Aero Squadron and began active operations over the front. It was equipped with SPAD S.XIA.2s aircraft. In combat, the mission of the 12th Aero Squadron was general surveillance of the enemy rear areas by means of both visual and photographic reconnaissance. These missions were carried out for the purpose of intelligence-gathering and informing First Army headquarters informed of enemy movements and preparations for attacks or retreats of its infantry forces. The 12th identified enemy activity along roads and railroads, ground stations, various storage dumps and airfields; the numbers of fires and activities of enemy aircraft, and the amount of anti-aircraft artillery was also monitored and reported. Due to the nature of the missions and the depths of enemy area which was penetrated, the missions were carried out at high altitudes, usually between 4,500 and 5,500 meters.
With few exceptions, the 12th’s pilots had never flown combat, but most of the observers had spent a number of weeks flying with French squadrons on active missions. One of these, Lieutenant Stephen W. Thompson, was at the 1st Squadron Gunnery School at Cazaux Airdrome, near Bordeaux when he was loaned on 5 February to the 123d French Breguet Squadron due to a shortage of observers in that unit. Returning from a bombing raid on Saarbruken, the aircraft in which Lt Thompson was operating the rear guns was attacked by German Albatross pursuit ships. He shot one down, becoming the first man in an American uniform to shoot down an enemy airplane. Later, on 28 July 1918, as a member of the 12th, he was credited with two more "kills."
The 12th’s operations in the Toul Sector was a seasoning period for the squadron as it gained experience over a relatively inactive front with almost no enemy air opposition. "On the other hand," according to an Air Service report after the war, "the enemy antiaircraft fire in the sector was exceedingly dense, active and accurate. Pilots of the Group were adept at evading antiaircraft fire after a month in the sector." On 10 June, the 12th Aero Squadron moved to the Baccarat Sector and to the unfinished Flin Aerodrome, from which they supported the 42d American and 167th French Divisions. There, the 12th began to receive the latest in French observation aircraft, the Salmson 2A2. This front, too, was considered "stabilized" or quiet, but the opposing German air force, while not flying the latest types, was active and aggressive. The 12th flew visual and photographic reconnaissance, adjusted artillery fire, and staged "infantry-contact patrols" to locate the front lines.
12th Aero Squadron