At the outbreak of hostilities, the surviving 39 Hs 123s assigned to II. (Schl)/LG 2, were committed to action in the Polish Campaign. This single unit proved to be particularly effective. Screaming over the heads of enemy troops, the Hs 123s delivered their bombs with devastating accuracy. A frightening aspect of an Hs 123 attack was the staccato noise of its engine that a pilot could manipulate by changing rpm to create "gunfire-like" bursts. The Hs 123 proved rugged and able to take a lot of damage and still keep on flying. Operating from primitive bases close to the front lines, the type was considered by ground crews to be easy to maintain and reliable in field conditions.