Boeing 707 lb (57.8 kN) with water injection. Maximum takeoff weight was 247,000 lb and first flight was on December 20, 1957. Major orders were the launch order for 20 707-121 aircraft by Pan Am and an American Airlines order for 30 707-123 aircraft. The first revenue flight was on October 26, 1958; 56 were built, plus seven short-bodied −138s; the last −120 was delivered to Western in May 1960. The 707-138 was a −120 with a fuselage 10 ft shorter than the others, with 5 ft (three frames) removed ahead and behind the wing, giving increased range. Maximum takeoff weight was
1977 Dan-Air Boeing 707 crash that investigation are as follows: It was determined that the structure of the right horizontal stabiliser failed due to metal fatigue in the rear spar structure, and due to the lack of an adequate fail-safe structure or device should such an event occur. The investigation also identified deficiencies in the assessment of aircraft designs and their certification and in the way aircraft were inspected. The Boeing 707 320/420 series had an enlarged horizontal stabiliser (tailplane) assembly compared to earlier 707 aircraft, and in the redesign the increased loads on the tailplane structure had been taken by replacing some of the