Increasing demands for replacement personnel shortened the time pilots spent in training courses. In the spring 1942 most new VVS pilots were inadequately trained. Difficulties such as these were exacerbated by the teething problems encountered during the introduction of new aircraft types. The difficult combat situation forced the Soviets to send pilots into action in aircraft types with which they were not completely acquainted. Poorly trained Soviet pilots with new aircraft types (with as little as eight hour on type in their logs), versus the well-trained German fighter pilots with experience gained from hundreds of combat situations on the same aircraft types. That was the situation of the air war in the spring and summer 1942.