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 maintenance, and the aircraft had been flown for a considerable number of hours with the fault present. Over time the crack grew, until it was surmised, the damaged spar was no longer capable of carrying its designed load, whereupon the load was then taken over entirely by the front spar. The accident aircraft encountered several strong gusts during the approach immediately before the accident which, while not dangerous to a structurally sound Boeing 707, exceeded the load capable of being carried by the remaining intact spar on its own, leading to the spar eventually breaking and resulting in complete structural