Complex sentence: First flown in 1948, the Viscount was the world's first turboprop powered airliner to enter service, subsequently being the first of its type to use a jet turbine engine as a part of its propulsion.
Split into simpler sentences: First flown in 1948, the Viscount was the world's first first turboprop powered airliner to enter service. The plane was also the first to use a jet engine as a part of its propulsion.