Complex sentence: No.II was damaged in a heavy landing and re-built as the No.IIbis, it flew at least once in April 1909 before being destroyed when the company's works were badly damaged in a severe storm.
Split into simpler sentences: No.II was damaged in a heavy landing and was rebuilt as the No.IIbis. It flew at least once in April 1909 before being destroyed when the company's works were badly damaged in a severe storm.