Complex sentence: Ripper orders his executive officer, Group Captain Lionel Mandrake of the RAF, to put the base on alert, asserting that it is not a drill, and orders him to issue Wing Attack Plan R to the aircraft.
Split into simpler sentences: Ripper orders his executive officer, Group Captain Lionel Mandrake of the RAF, to put the base on alert, asserting that it is not a drill. He also instructs Mandrake to issue Wing Attack Plan R to the aircraft.