1977 Dan-Air Boeing 707 crash

The aircraft was a Boeing 707-321C that first entered service with Pan American World Airways (Pan Am) in 1963. This aircraft was also the first convertible 707 built, operated, as well as the type's second turbofan-powered and second convertible example in service with the airline. At the time of the accident, it had flown about 47,000 hours. ==History of flight==

The flight was a three-legged originating from London Heathrow Airport to Athens (Hellinikon Airport), which was uneventful; from Athens it then proceeded to Nairobi (Jomo Kenyatta International Airport). Departure from Nairobi for Lusaka on the final leg occurred as planned at 07:17, 14 May. The 707 cruised at flight level 310 for about two hours, after which it was cleared for descent to flight level 110. Flight level 110 was reached at approximately 09:23, and clearance was granted to begin descent towards a target of flight level 70. Just before 09:30, clearance to descend to was granted, and moments later the plane was cleared to make a visual approach to runway 10. A few minutes later, witnesses saw the entire right horizontal stabiliser and elevator assembly detach from the aircraft. The aircraft subsequently lost pitch control and entered a nose-dive from about to ground level, destroying the aircraft on impact. There were no survivors among the five crew members and one jumpseat passenger on board the aircraft. There were no other fatalities on the ground. The wreckage was located approximately from the runway. ==Investigation==

A full investigation was launched by the Zambian authorities and the investigation was then delegated to the UK Air Accidents Investigation Branch - AAIB. The conclusions made by 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. ==Notes==