The resulting DB-A was advanced for its day, with stressed skin aluminium alloy construction throughout with clean lines, neatly cowled engines and trousered main undercarriage legs, with fully retracting main-wheels and tail-wheel.

The split flaps, undercarriage, nose turret and bomb-bay doors were all operated by a pneumatic system recharged by engine-driven compressors.

The excellent performance demonstrated included, sustained flight at an altitude of 2,500 m (8,202 ft) with two engines shut down, and 4,500 km range.

The red-painted DB-A prototype under command of Sigizmund Levanevsky departed Shchyelkovo airport on 12 August 1937 on an attempt to fly to Fairbanks, Alaska.

A second aircraft with increased gross weight, improved airframe, re-designed nose and more power was completed and flown in March 1936 as the DB-2A.