However, it became obsolete after a short use period, mainly because of fast-improving aviation technology, as well as the USAAC's desire for multi-engined attack aircraft.

This was a response to the USAAC's move toward a preference for radial engines, especially in attack aircraft.

The rationale behind this preference is that the radial engine has a lower profile, making it less vulnerable to ground fire, and a simpler cooling mechanism, which is also less prone to groundfire, as well as overall maintenance problems.

[2] These aircraft retained the open cockpit introduced in the A-8 production batch, and carried the same weapons load.

[4] On 15 August 1937, during the start of the Sino-Japanese War/World War II in the Battle of Shanghai, the Imperial Japanese Navy launched 45 planes from the fleet aircraft carrier Kaga targeting Chinese Air Force assets in the province of Jiangsu surrounding Shanghai; thirteen Aichi D1A1 dive-bombers were unable to find their intended target in Suzhou and so diverted to Jianqiao Airbase instead, but stumbled upon A-12 Shrikes of the 26th and 27th Squadrons of the 9th Attack Group at the Chao'er auxiliary airbase preparing for strikes against Japanese positions in Shanghai, and a dogfight ensued between two unlikely dogfighting opponents: two D1A1s were shot down by the Chinese A-12s, and another badly shot-up D1A1 returned to Kaga with a fatally wounded crewman.