Complex sentence: The Iroquois was originally designated HU-1, a designation that led to the "Huey" nickname, which has remained in common use even after the Iroquois was officially redesignated UH-1 in 1962.
Split into simpler sentences: The Iroquois was originally designated HU-1, which led to its "Huey" nickname. The helicopter has remained in common use after the official designation was changed to UH-1 in 1962.