Complex sentence: The Helgoland Island Air Disaster occurred on September 9,1913 when the airship Zeppelin LZ 14 was transferred to the Imperial German Navy on 7 October 1912.
Split into simpler sentences: The Helgoland Island Air Disaster occurred on September 9,1913. Manufactured by Zeppelin as the LZ 14, the airship was transferred to the Imperial German Navy on 7 October 1912.