Lufthansa Flight 540 was a scheduled commercial flight for Lufthansa, serving the Frankfurt–Nairobi–Johannesburg route. On 20 November 1974, the Boeing 747-130 that was operating as Flight 540 was carrying 157 people (140 passengers and 17 crew members) crashed and caught fire shortly after taking off from Jomo Kenyatta International Airport in Nairobi for the last leg of the flight, resulting in the deaths of 55 passengers and 4 crew members. This was the first fatal accident involving a Boeing 747. Aircraft and crew Aircraft The aircraft involved was a Boeing 747-130 registered as D-ABYB and was named Hessen. It was the second 747 to be delivered to Lufthansa. It made its first flight on 30 March 1970 and was delivered to Lufthansa on 13 April the same year. The aircraft was powered by four Pratt and Whitney JT9D-7 turbofan engines. The aircraft had 16,781 flying hours at the time of the accident. Crew The flight crew consisted of 53-year-old captain Christian Krack (who had more than 10,000 flight hours, with 1,619 hours on the Boeing 747), 35-year-old first officer Hans-Joachim Schacke (3,418 flight hours, with more than 2,000 hours on the Boeing 747) and 51-year-old flight engineer Rudolf (Rudi) Hahn (13,000 hours of flying experience). Accident As the aircraft was making its takeoff from runway 24 at the Jomo Kenyatta International Airport in Nairobi, the pilots felt a buffeting vibration. The captain continued the climb and retracted the landing gear. However, as this was being done, the aircraft started to descend and the stall warning system light came on. The aircraft continued to descend and approximately from the end of the runway, the 747 airplane crashed in the grass. It then struck an elevated access road and broke up. The left wing exploded and fire spread to the fuselage. 55 of the 140 passengers and 4 of the 17 crew members died. Cause The cause of the crash was determined to be a stall caused by the leading edge slats (strictly speaking, outboard variable camber leading-edge slats and inboard Krueger flaps) having been left in the retracted position. Even though the trailing edge flaps were deployed, without the slats being extended the aircraft's stall speed was higher and the maximum angle of attack was lower. As a result, the aircraft was unable to climb out of ground effect. The flight engineer was found to have failed to open the slat