Complex sentence: He went on to be Commandant of the Central Fighter Establishment in 1954, Commander of Operation Grapple (the Hydrogen Bomb testing programme) in 1957 and Assistant Chief of the Air Staff (Operations) in 1958.
Split into simpler sentences: He went on to be Commandant of the Central Fighter Establishment in 1954. He became Commander of Operation Grapple (the Hydrogen Bomb testing programme) in 1957 and Assistant Chief of the Air Staff (Operations) in 1958.