Complex sentence: On 5 August 1950, a nuclear-capable United States Air Force Boeing B-29 Superfortress bomber carrying a Mark 4 nuclear bomb crashed shortly after takeoff from Fairfield-Suisun Air Force Base with 20 men on board.
Split into simpler sentences: On 5 August 1950, a Boeing B-29 crashed at Fairfield-Suisun Air Force Base. The nuclear-capable United States Air Force B-29 Superfortress bomber carrying a Mark 4 nuclear bomb crashed shortly after takeoff with 20 men on board.