WWI: Spotting for the Army’s Big Guns II

1916 Caudron GIII artillery spotting – Paul Lengelle

In terms of artillery observation, the United States entered the First World War entirely dependent on the French and British for preparatory operational assistance on the modern battlefield. The American Expeditionary Force came to Europe with outmoded battle doctrines that anticipated a war of movement rather than the stagnant state of trench warfare practiced on the Western Front. Mobile warfare doctrine put artillery in an auxiliary role, subordinate to the infantry, rather than casting it in the lead and supposing it would help to achieve breakthrough. In the years prior to the war, the US Army had failed to prepare its artillery any better than it had built up its air power. When the first American units arrived in France two months after the declaration of war, they came without artillery. By the armistice the US Army had nearly 3,500 pieces. As the nation eventually did with its Air Service, the United States solved its artillery problem by purchasing most of its equipment from the French. The other element necessary to an effective artillery program, an observation system, also had to be built from scratch.

Possessing neither an air force nor an aerial doctrine, the United States had to act quickly to build an aviation organization capable of operating with its artillery units in France. The Army and Navy used the nearly $640 million Congress provided both to build and buy aviation equipment. Most of the material the American Expeditionary Force acquired abroad came from French factories.

American artillery officers realized how vital effective aerial observation had become and they attempted to address the problem quickly. They began training their own observers at artillery brigade training centers immediately after the arrival of the first US artillery units in France. The Air Service also began to train observers, but the artillery refused to entrust its officers to the Air Service at this early stage of American participation in the war, citing the necessity of its personnel training with their own units so they might become versed in French artillery methods. This arrangement proved unsatisfactory because the observers instructed by the artillery learned only how to work with the artillery without training in any other aircrew skills. In response the Army created an Air Service observation training organization. The basic course of instruction ensured the new observer finished training with at least elementary skills in the entire range of aerial observation topics, including reconnaissance, photography, infantry contact, and artillery observation. Subsequent advanced training in the finer points of artillery regulation took place in advanced schools placed next to the artillery training centers where artillery and aviation officers could train together in mock combat situations. In September 1917 the Army designated Tours, France, as the location of the Observers’ School and the first trainees began instruction there in January 1918. Sites for the advanced artillery aerial observation schools (AAOS), named in October, included: Coetquidan (1st AAOS), Souge (2nd AAOS), Meucon (4th AAOS), and LeValdahon (5th AAOS).

In addition to the French airplanes the US Air Service purchased, American aviators also accepted French artillery-observation methodology. American observer training in France generally followed French methods by employing instructional materials that were little more than translated French manuals. The US Army’s decision to follow the French in its approach to artillery regulation might reflect more than its intent to operate in closer contact to French units than to the British. When the United States entered the war the British conceded their French counterparts did better at artillery spotting than their own army, “owning chiefly to close co-operation between the officer commanding the French Artillery and the aircraft attached to it.”

Students in the advanced courses were expected upon their arrival to know the characteristics of the various artillery pieces then in use, including the French 75- and 155-caliber guns, and the differences in various types of shells. During the course the cadet observers practiced firing 8-second salvos in three-, four-, and six-round series. Instructors emphasized combining speed and accuracy when adjusting the 155-caliber gun, but were willing to sacrifice speed for greater precision when adjusting the 75-caliber. Of the 1,250 officers who commenced training over the course of 1918, just over seven hundred were serving at the front at the time of the armistice.

The US Air Service recruited students for the observer courses from three sources: men trained in the United States, candidates furnished by the artillery, and volunteers from all other arms of the AEF. The second and third sources became necessary because the stateside training program never yielded sufficient numbers. Air Service officials in France regularly complained that domestic trainers could not meet their personnel requirements and that the deficiencies had to be made up in Europe. Late in the war recruiting efforts within the AEF started to dry up as well, prompting the Air Service command in France to suggest as an incentive that cadets be provisionally commissioned prior to leaving the United States, with their commission becoming permanent only upon successful completion of the observer’s course. Further, the American recruiting program suffered qualitatively as well as quantitatively. Observers who began their training in the United States frequently arrived in France either inadequately schooled or instructed in methods long out of use at the front, necessitating lengthy retraining.

Beyond recruiting enough capable men to serve in the cockpits, the US Army faced the equally daunting challenge of convincing those designated for observation training that their work represented aviation’s most valuable contribution to the war. Captain Harold Wilder, a US Air Service artillery observation trainer, told his students, “Observation comprises the Air Service which acts in direct connection with the other branches of the Army. Complete contact with these branches has been a primary object of the Service and its results have been in proportion to the success of this cooperation.” Regular training bulletins issued by the Air Service reminded the observation pilot of his worth, telling him that “it is a mistaken idea some flyers have that a pilot who has been sent to observation is a cast-off in chasse.” The Air Service’s persuasive efforts put strong emphasis on the notion that “all aviation is built around observation.” The training bulletins touted accounts of observation’s successes, including the story of an American crew credited with saving a division that compared the feat to the best a fighter pilot had ever achieved: “There should be more satisfaction to these two men for what they did than for the honor of bringing down six Hun planes in a day.”

When the nature of artillery observation began to change as trench warfare gave way to movement in the conflict’s final months the Air Service used its training bulletins to instill the level of confidence observers needed to stand up to the battery commander. Articles in the bulletins reminded observers “the big trouble at present seems to be in the adjusting on fleeting targets. When an observer calls for an adjustment they must fire on that target or else send him ‘No’ and not adjust on a different target as some have done when given a target of importance by an observer.”

Convincing the aviation cadets of the value of their work and instructing them in the proper techniques of artillery observation represented only half the training equation. Building the relationships necessary between front-line aviation and artillery units in order to field an effective destructive force comprised the other half. Maximizing the potential lethality that artillery brought to the modern battlefield required that the men firing the shells understood the value of those observing for them in the sky and that the two branches communicated on an ongoing basis. To foster this appreciation for aviation within the artillery, Air Service instructors at the artillery schools designed a short course for artillery officers comprised of three lectures: a general introduction to artillery’s role when using air observers, and two lectures that used stereopticon slides to instruct students in how to use aerial photos in planning artillery fire and designing camouflage. Experience would prove that classroom instruction alone did not produce complete results. Only working together in the field would achieve the strong link between aviation and the artillery essential to victory in combat. Artillery officers needed to become fliers.

By the summer of 1918 the US Air Service had several months’ experience training and using artillery officers as balloon observers when it decided to effect the same blend in its corps observation squadrons. The immediate shortage of qualified trainees arriving from the United States as well as the desire for observers with a broader technical knowledge of artillery work prompted the change in policy. Training began so quickly that of the 193 observers who graduated from the Second Aviation Instruction Center at Tours in September 1918, the majority had come from the artillery.

As important as good training might have been, indoctrinating artillery officers in the ways of aviation and aviators in artillery techniques constituted only the first steps towards building a successful artillery observation organization. The rest of the effort had to take place in the field. Meaningful liaison between the two branches had to become so much a part of the regular routine of both services that it permeated Army culture. The effort to build this new culture started at the top of the Army’s organizational chart and flowed down to the level of the individual squadrons and batteries. To achieve this the Air Service stationed liaison officers at each divisional headquarters to work directly with the division’s commanding general in the selection of each day’s targets. Artillery commanders notified the Air Service which of the targets had been allocated to terrestrial, balloon, and aircraft observers, and the Air Service assigned the appropriate units to the operation. Their efforts were not always immediately successful. Commenting on their coordination with ground units, Air Service trainers remarked:

Liaison between the Air and the Ground is very poor with new divisions, as these men have not understood the full value of the airplane. Artillery liaison is also poor, especially in the work with fugitive targets. In order to encourage liaison, these observers should be encouraged to visit the unit with which they will be working as often as possible so that they may secure this cooperation and show them by practical experience what the value of the aeroplane really is.

If the Air Service hoped to become a truly effective battlefield asset its efforts to improve liaison between air and ground units had to reach down the chain of command to the level of the individual air squadrons and artillery batteries. As a start, squadron commanders attending the nightly conferences at which the next day’s targets were arranged and allocated were instructed to bring along a few of their observers. While their commanding officer obtained the latest intelligence data from division headquarters the observers discussed target specifics with the artillery commander. Success during the battle required at least a partial division of authority between air and ground units. Battery commanders had responsibility for the success [of the shoot] and the air observer generally acted in a subordinate role, but the observer had the ability to exercise his own judgment and intervene under limited circumstances. The observer could suggest the use of precision or zone fire, but the actual decision belonged to the battery commander. If the battery suffered a delay for any reason and could not fire within thirty seconds of the air observer’s signal, procedures required that it hold its fire until it received another signal from the aircraft. To facilitate cooperation to an even greater degree the Army developed forms for use in the field; an “objective card” which illustrated the location of the target on both a map and a photograph and, for occasions when wireless signals proved impossible, a form the observer could drop to the battery to convey urgent firing instructions. Artillery observation thus became part of the US Army’s bureaucracy.

The French can take credit for the centerpiece of systemization, which had been in place long before the American Expeditionary Force arrived on the Western Front. The Plan Directeur, a 1:20,000-scale map, pulled together every bit of intelligence data available to the Army and verifiable by aerial photograph to depths of 10 kilometers inside German lines and 5 kilometers inside Allied territory. French Army Intelligence updated the map daily and issued it as the basic artillery map. Mapmakers supplemented the Plan Directeur with 1:10,000-scale trench maps that included “wire, obstacles, dugouts, trails, and important details of trench organization,” and 1:5,000-scale infantry maps that detailed both the German and Allied sides of the lines. Throughout its stay on the Western Front, the AEF used these French maps as its basic day-to-day artillery guide.

Conducting an effective artillery firing session required more than the development of trust between aircrews and their gunners and designing a well-organized system. It also required regular practice. When a sector of the front went quiet and the artillery did not need regular adjustment, the Air Service’s squadrons devoted their time to general reconnaissance and photography duties in preparation for the next rounds of heavy fighting. Valuable as this preparation proved to subsequent operations, the downtime frequently resulted in diminishing skills in both airmen and gunners. Operations officers encouraged observers to avoid this problem by insisting they call upon the artillery to engage fugitive targets during their routine reconnaissance flights. Air Service trainers advised the operations officer to resort to shame if necessary to stave off the possibility of his teams falling into a “live and let live” philosophy, reminding them, “It is a very mediocre observer who cannot pick out some target of immediate value during a reconnaissance.”

Practice paid dividends both in terms of the artillery’s accuracy and in the development of new techniques. From its rudimentary beginnings in the summer of 1914 the science of artillery observation had developed by the last months of the war into a highly organized and destructive program practiced by all the warring powers. The German Luftstreitkräfte felt sufficient confidence in its techniques and its artillery fliers to begin experimenting with night ranging during 1918 on the French and British fronts. The observer could establish his location through the use of natural landmarks or be pointed towards the target with flares set up by the battery. Darkness required that he guard against his vision being dazzled by the fire and that he identify bursts by their “circular form” and flash discharges by their “bright semi-circular glow.” Apart from these special instructions, work proceeded along firmly established lines laid out in the Manual of Position Warfare for All Arms.

Not satisfied with simply fine-tuning daytime techniques for use after dark, German artillery fliers began experimenting with ranging their guns with photographs rather than human observers. The new method required more cooperation between aviation and artillery than any simple pre-fire conference. The process began with an artillery battery taking a few ranging shots, after which a reconnaissance crew would photograph the area shelled. Mathematicians would use shell holes visible on the photographs to calculate a datum point for use in ranging the guns, eliminating the need for an observer to be present during the actual shoot. The US Air Service Chief of Staff Col. Thomas D. Milling proposed an easy, if rather ludicrous-sounding, countermeasure to this German experiment, suggesting that if the enemy’s practice firing occurred late enough in the day that the reconnaissance flight might not appear until the following morning troops would spend the night filling in the real shell holes and replacing them with fakes in other locations.

The US Air Service and its partners in the artillery began learning these lessons during the spring of 1918 when the first corps squadrons arrived at the front. During July and August the AEF engaged in its first real battle at Chateau Thierry. For that campaign the 1st Aero Squadron found itself assigned to corps reconnaissance and artillery adjustment duties while the 12th and 88th Aero Squadrons handled divisional work, which included regulating the divisional artillery as well as providing for general and special reconnaissance, infantry contact, and special command missions. The artillery sorties performed by the three units penetrated enemy lines to a depth of 1,000–2,500 meters, shorter-range observations being handled by ground spotters or balloon crews.

Valuable and sophisticated as Allied artillery adjustment techniques had become over the four years since the start of the war, the doctrines the French and British had formulated and passed along to the AEF focused on principles that applied to stationary, not open, warfare. When the German lines finally began to give way to Allied attacks and American, British, and French forces started advancing, those principles broke down. Artillery regulation became a difficult proposition during a war of movement. In a rush to follow up on their breakthroughs, and hampered by habits acquired over long years of not needing to communicate with aviators, American artillery batteries did not always let their corps squadrons know where to find them. The US Army did not have the time to resolve these communication problems in the few weeks that remained in the war. As a short-term remedy, artillery officers reverted to ground spotters and balloons during open warfare, reserving airplanes for circumstances where observation would have otherwise been impossible. Another method of dealing with fugitive targets was to assign to patrol duty an aircrew familiar with the zones of the various regiments. The crew would call down the various targets available and the regimental commander would decide which ones to attack.

Though hampered by the same communication problems, their lengthier experience allowed the British and French air forces to adapt more quickly than their American colleagues to the return to mobile warfare. By late September 1918, British historian Hilary St. George Saunders boasted, “the Royal Air Force was everywhere, and this time so carefully had the system of signaling to the artillery been devised and rehearsed, that, despite the swift movement of the battle, its Corps squadrons were enabled to direct the guns again and again on to suitable targets.”

Though American aviators’ and artillerists’ relative inexperience in the art of modern warfare hampered their ability to make the rapid changes frequently necessary to effective inter-branch cooperation, the achievements of French and British forces did succeed in convincing the Army that a strong aviation program constituted an element essential to victory in modern combat operations. Outlining the requirements for an army of one million men in 1918, the War Department proposed that the Army’s Air Service component consist of twenty-four observation squadrons, fifteen pursuit units, five bomber squadrons, one photographic section, twenty-four balloon companies and six air parks. Nearly two-thirds of these units (the observation squadrons, balloon companies, and the photographic sections) provided direct assistance to the artillery, the balloon companies doing almost nothing else.

The composition of the US Air Service by the time of the armistice demonstrated that strong emphasis on artillery regulation. Of the forty-five airplane squadrons that made it to the front lines by November 11, 1918, twelve had corps reconnaissance as their exclusive duty. Including the seventeen balloon companies at the front on the last day of the war, the number of Air Service units devoted to artillery observation rose to twenty-nine within a total of sixty-two (46.7%) heavier- and lighter-than-air units. Those numbers put the US Air Service in line with the French aviation program from which its leaders took their primary example. During the last seven months of the war the French had 230 escadrilles on the Western Front, 107 of which worked with the artillery. By contrast, on the war’s last day the British Royal Air Force had ninety-nine heavier-than-air squadrons, seven independent flights, and nineteen balloon companies on the Western Front. Although the RAF devoted more effort to aerial combat and bombing and comparatively less to reconnaissance than did its American and French counterparts, corps observation units still made up twenty of those ninety-nine squadrons and the RAF’s official history boasted that British aviators had registered the fall of twelve million shells. Another historian estimated that 80 percent of the British artillery’s targets had been obtained from the RAF.

Assessing lessons learned during the war after the armistice, US Air Service trainers formulated techniques to use during future periods of static and open warfare. Looking back they noted that good liaison work had become even more important while troops were on the move due to the large number of fugitive targets available. Acknowledging the problems artillery battery commanders had keeping in touch during the Meuse-Argonne offensive, the trainers suggested that battery commanders not make adjustments in open warfare using the customary battery-target line, but instead by using as reference points the old signaling panels laid out by each battalion station. They further recommended that observers then pinpoint shots in a manner similar to zone fire by signaling whether the shell landed to the right or left of the panel. Acknowledging these suggestions would yield imprecise results the trainers proposed that the artillery revert to the more established principles that had proven successful during the fighting once ground movement slowed down or stopped long enough for squadrons to reestablish contact with individual batteries.

Whether fighting from the trenches or on open ground, the days when the artillery had to rely on the cavalry to capture the high ground in order to see its targets had ended. Using aerial observers in airplane cockpits and balloon baskets, the big guns could hit targets previously thought impossible to spot. The range of the guns now constituted the only limitation to the size of the battlefield. The major air forces that served on the Western Front and in the other theaters of war, even those that took a more aggressive approach to the conflict, considered it their primary job to assist their counterparts on the ground in taking the fight to the enemy. Aviation had become an integral part of all armies and a vital component to military success on the ground. Air power provided the ability to see what happened “on the other side of the hill” and held the key to making the artillery more deadly than it had been in any previous war.


Leave a Reply