The Citation II, Model 550, was a direct development from the Citation I. The earlier aircraft’s success in the market led Cessna to believe there was demand for a larger aircraft that utilized the same design philosophy. The result was the Citation II, which had a maximum seating capacity of 10. In addition to more seats, the plane had more powerful JT15D4 engines, faster speeds and longer range. First flight was on January 31, 1977, and the aircraft was certified for two-pilot operation in March 1978. A total of 603 aircraft were built before the Citation II was replaced by the Bravo in the production line. Citation II/SP Like the Citation I/SP, the Model 551 Citation II/SP as Cessna’s means of competing in the turboprop market, which predominantly are operated single-pilot, so the aircraft was re-certified for single-pilot operations.