Aerial reconnaissance in World War I

Early operations were low-level flights with the pilot often dismounting from the plane to report verbally to the nearest officers.

Reconnaissance remained an under-rated military art, compared with aerial combat, which gained the publicity, but impacted less on the outcome of the war.

While most of the combatant countries possessed a few military aircraft in August 1914, these were almost exclusively devoted to reconnaissance and artillery spotting, supplementing well-tried and familiar platforms like balloons and kites.

Dirigibles like the huge new German Zeppelins were considered the best reconnaissance platforms and they served effectively for maritime patrols.

In time, longer focal length lenses were used, cameras and gear grew lighter and bigger, and for survival, operating altitudes increased up to 12,000–18,000 feet (3,700–5,500 m).

For artillery spotting, time was of the essence, and the French tried air-dropped messaging, colored flares, and pre-arranged aircraft maneuvers to convey information.

In stark contrast with the French, early British reconnaissance was essentially conducted on an amateur basis, lacking in official backing.

[2] Major Bagley brought his recently invented tri-lens camera to France, where it was used to make one vertical and two oblique images from airplanes.

The T-2A had one vertical lens and three oblique lenses set at 35 degrees, which provided a 120-degree field of view at right angles to the direction of flight.

Despite the improvised start, all sides quickly learned the importance of aerial photography, and by 1916 heavier-than-air reconnaissance was a regular practice along the front.

Support of ground forces was almost the sole role of reconnaissance; strategic air war concepts were as yet embryonic.

By the end of the war both sides maintained detailed maps of the front derived from mosaics of aerial photographs.

The more capable but similar R.E.8 replaced the B.E.2c as the standard RAF reconnaissance aircraft and remained in that role despite requiring escort for survival.

The radio-equipped unarmed photoship Rumpler C.VII (Rubild) — for Rumpler-Bildflugzeug (picture-aircraft)[4] — distinguished itself for long-range and high-altitude, reaching 21,000 feet.

Unusual recon aircraft included the armored Junkers J.I for low-level flights, the gigantic long-range Ilya Muromets from Russia, and the high-performing (at well over 200 km/h top speed) Italian Ansaldo SVA, considered nearly uninterceptable.

When the U.S. entered the war, the Army urgently requested that American civilians turn in their lenses and optics, including telescopes and binoculars, for aerial use, specifically naming several sought-after German manufactures.

The attempts at Allied interoperability was thus described at the time: “The task of harmonizing the photographic practice as taught in America, following English lines, with French practice as followed in the theater of war, and of adapting planes built on English designs so that they could carry French apparatus, was a formidable one, not likely to be soon forgotten by any who had a part in it.”[5] Overlapping stereoscopic photos began to be taken, requiring carefully timed exposures.

Despite some experiments, night photography was unsuccessful due to insufficient flash power and film speed, and inability to precisely time the exposure to the illumination.

Equally importantly, interpreters learned to standardize annotations and present comprehensive marked-up imagery to commanders.

The static fronts and fixed fortifications in Europe were especially suitable for turning the art of interpretation into a science, while the far-ranging operations in the desert and at sea put a great premium on serendipitous discovery and resourcefulness.

In four years, commanders learned that reconnaissance innately favors the defensive, as it reduces surprises and makes it difficult for the opponent to mass forces for attack.

Inability to conduct reconnaissance, such as due to weather or enemy air domination, conversely leaves one highly vulnerable, as occurred repeatedly during the War.

[6] Perennial problems included the shortage of trained and experienced photo-interpreters, the difficulty in distributing timely and interpreted prints to exactly the commanders needing them, a lack of overall coordination of effort and centralized interpretation (a common air picture), and the tendency of field commanders to demand risky, repeated flights for objectives only for the photos to languish in files somewhere along the process.