Complex sentence: On 23 August 1921, "R-38" was destroyed by a structural failure while in flight over the city of Hull and crashed into the Humber estuary, killing 44 out of the 49 crew aboard.
Split into simpler sentences: On 23 August 1921, "R-38" was destroyed by a structural failure while in flight over the city of Hull. It crashed into the Humber estuary, killing 44 out of the 49 crew aboard.