[4] During the inactive period on the Toul sector covering the late spring and summer of 1918 and up to the St. Mihiel offensive which commenced on 12 September, army observation in the American Air Service was carried out by one unit, the 91st Aero Squadron.

He decided to utilize the American pursuit all along the front for the purpose of protective barrage at all altitudes, with incidental duties as occasion arose, of a more combative nature, such as ground strafing, balloon destruction, and offensive patrols.

Some intimation of an impending allied offensive in this sector had reached the enemy, and immediately preceding the attack of 12 September he commenced a redistribution of his available forces, especially with a view to echeloning them in depth.

Individual observation and photograph airplanes operated over the sector, but no unusual number of hostile aircraft was at any time encountered or reported before the opening of the Saint-Mihiel offensive.

The information secured in this manner was for the most part of a negative nature, due to the inactivity of the enemy at this period, but it served the purpose of assuring the staff of each corps that there were no new developments in the general tactical situation.

[2] Photographic reconnaissance, during the period of preparation, consisted for the most part of taking oblique views of the enemy territory immediately opposite the front lines of each corps.

[7] During the period preparatory to the attack, from 29 August to 12 September, the 1st Pursuit Wing, working on the front between the Meuse and the Moselle Rivers, maintained patrols sufficient to prevent any reconnaissance, visual or photographic, of the area Lionville, Beuconville, Domeurs, Francheville, Becq and Gironville.

Some close protection work was ordered to act in cooperation with the army reconnaissance squadron, and one particularly dangerous balloon near Mont Sec was attacked repeatedly.

During the four days of the American offensive which cleared the St. Mihiel salient of the enemy, weather conditions, except on 14 September, were such as to greatly hinder the carrying out of aerial operations.

On the morning of 12 September, when the attack was launched, a heavy mist, low-lying cloud banks, and intermittent rain combined to make all aerial observation extremely difficult.

The command was thus kept informed of the general progress of the battle and at periodic intervals was given the first line of our advancing troops located by observers executing the missions of infantry contact.

Some of the best enemy flights operated along the sector and observation airplanes were repeatedly attacked, but in the majority of cases successfully defended themselves and accomplished their assigned missions.

[5] However, owing to the prevailing adverse weather conditions, it was necessary to disregard the schedules that were prepared the preceding day as the low hanging clouds rendered formation flying impossible.

The effective work done and the comparatively small number of casualties suffered during the St. Mihiel offensive, gave evidence of the excellent training and experience gained during the previous three months.

To interfere with traffic of reinforcements and supplies from the sector east of the Moselle river it was found expedient to send bombing expeditions against the bridges, and bridgeheads, between Pont-a-Mousson and Metz.

[7] Late at night, 11 September, orders were received to hold the 9th Aero Squadron on the alert early in the morning, to bomb and machine gun hostile troops in front of our advancing infantry.

Consequently, that the order be obeyed, the leading team of the first flight volunteered to attempt the mission alone, and to determine, if possible, the best method of conducting troop bombing under the existing unfavorable conditions.

Large enemy formations of aircraft when they appeared were fought gallantly even by inferior members, and every opportunity of making observations from pursuit planes was seized with eagerness.

There were occasional ideal flying days, but for the most part weather conditions were poor to impossible and proved a great handicap in carrying out aerial operations.

Atmospheric conditions were so infrequently favorable to the taking of large numbers of photographs that those possible were necessarily directed to cover areas of the most immediate interest to the staff.

This method allowed the pursuit airplanes to retain the advantage of their maneuverability and at the same time to assure to the photographic mission considerable protection in the event of attack.

This fact, coupled with the activity of the hostile air forces, interfered greatly with the success of the photographing of the artillery objectives, and to some extent with the visual work.

[5] One of the most valuable pieces of work carried out during the last three days of October was the photographing of the army artillery objectives at Montmedy, Longuyon, Spincourt, Dommary-Baroncourt and Conflans.

The command planes sometimes penetrated hostile territory to a depth of 15 kilometers, and were constantly exposed to heavy machine gun and anti-aircraft artillery fire.

The strain of flying under these conditions coupled with the necessarily close confinement while awaiting orders, made it necessary that the teams be changed every ten days, and personnel from each of the squadrons in the group were sent out on this work successfully.

The 1st Day Bombardment Group was used to attack, from high altitudes where possible, such towns as Romagne, St. Juvin, Grandpre, Bantheville, and Dun-sur-Meuse, and railroad centers from which traffic was radiating.

When intelligence was received of favorable targets within six or eight kilometers of the lines, the group was ordered to attack such objectives at low altitude to cause the maximum amount of confusion and damage to the enemy elements as reinforcements for retreating before our infantry.

[6] The 1st Pursuit Group in addition to its attacks on enemy balloons and its defensive work in destroying German battle-planes, was enabled to use shock action at low altitudes by means of a concentrated patrol of all squadrons which was made about three o’clock every afternoon.

[6] The policy employed with respect to the 1st Pursuit Wing of using large forces for shock action deep in the enemy's side of the lines, justified itself on the first day of the American attack in the Argonne Meuse area, 26 September.

Six Aero Squadrons, amongst the last to arrive at the front, were to be sent to the Rhineland to reinforce or relieve units of the Third Army Air Service, the remainder to proceed to Colombey-les-Belles Aerodrome, France for demobilization.