Background:
In the early 1970s, following the launch of the wide-body 747, Boeing began considering further developments of its narrow-body 727 trijet. Designed for short and medium length routes, the three-engined 727 was the best-selling commercial jetliner of the 1960s and a mainstay of the U.S. domestic airline market. Studies focused on improving the 189-seat 727-200, the most successful 727 variant. Two approaches were considered: a stretched 727-300, and an all-new aircraft code-named 7N7. The former was a
