In the first three days of the war, the commanders of the Soviet 3rd Air Corps still attempted to use their DB-3 bombers in their primary role, as a medium altitude level bomber, operating mainly at night. However the losses the Soviet aviation suffered were too heavy to allow such luxuries. By the 25th the 207th BAP (Bomber Aviation Regiment) of the 3rd DBAK (Long-Range Bomber Corps) was forced to launch small flights of unescorted DB-3s on low-level ground attack missions that these large lumbering aircraft were hardly suitable for. Having flown three conventional night-time bombing missions, Gastello was facing increasingly unfavorable odds. The day before his final sortie he returned to base with heavy battle damage, and his regular navigator badly wounded.