V4 prototype, and all later production runs of the A-series, used a DB 606 A or DB 610 A engine on the starboard wing, and one clockwise rotating B-version of the same powerplant on the port wing, so that the propellers rotated "away" from each other at the tops of the propeller arcs. The He 177 V4 was retained at Heinkel's test field at Rostock-Schmarl (then known as Rostock-Marienehe) where it undertook diving trials. While flying over the Baltic, the He 177 V4 failed to recover from a moderate dive, crashing into the sea near Ribnitz. It was discovered that the accident had resulted from the malfunctioning of an airscrew pitch control mechanism.