Which way did the AEG J.I's machine guns fire?

The AEG J.I's offensive armament consisted of a pair of 7.92 mm (.312 in) LMG 08/15 machine guns arranged so that they fired downwards. That orientation completely conditions how the aircraft was used: the fire was not directed forward, as in a fighter, but at the ground the biplane flew over, so the target was lined up by taking the aircraft directly above it. Both weapons shared the same calibre, 7.92 mm, and were fixed installations, with no possibility of retraining them in flight.

The aircraft was not left defenceless against whatever came from behind or from the sides. In addition to the two fixed LMG 08/15s there was a single Parabellum MG14 machine gun, also 7.92 mm (.312 in), mounted on a rotating mount that allowed it to provide flexible defensive fire. The difference between the two installations separates two distinct roles within the same aircraft: immobile guns aimed at the ground to attack ground targets, and a third that could be pointed in different directions for self-protection.

The J.I was not an isolated experiment. Counting the J.I and J.II together, around 609 aircraft had been built by the time the armistice came into force on 11 November 1918, placing the family among the German aircraft of its class produced in series and used until the final stretch of the conflict.