Lufthansa Flight 540 : The First Boeing 747 Fatal Crash, Why and How it Happened ?

Lufthansa flight 540 (D-ABYB)  pictured above 

The Boeing 747, Queen of the skies, took its first flight on the 9th of February 1969, initially ordered for Pan Am. As of June 2020, 1556 aircraft of such variants have been built, with 15 747-8s remaining to be delivered.

Just after 4 years in service, Lufthansa flight 540, carrying 157 people, crashed shortly after takeoff, on 20th November 1972, marking it the first fatal flight of Boeing 747.

Aircraft and AirCrew 

The aircraft D-ABYB named Hessen, was the 2nd Boeing 747-130 delivered to Lufthansa, D-ABYA being the first. The aircraft was powered by 4 Pratt and Whitney JT9D-7A Turbofan engines according to airfleets.net/ and had about 16,781 flying hours before the crash.

The crew consisted of Pilot in Command, Captain Christian Krack, having more than 10,000 flying hours, The first officer Hans - Joachim Schacke, and 51-year-old flight engineer Rudolf Hahn.

Flight Origin and Accident

Left-Wing Exploded on impact. causing fire to spread through the fuselage 

The flight was operating the Frankfurt - Naroibi - Johannesburg route. After taking off from Runway 24 of Jomo Kenyatta International Airport of Nairobi, The pilots felt vibrations to which landing gear was retracted and continued the climb. 

However, the aircraft started to descend and stalled shortly after 3700 ft from the runway. Upon impact, the left-wing exploded, causing the fire to spread through the fuselage of Lufthansa Flight 540 , Killing 55 of the 140 passengers and 4 of the 17 crew members. However, the 2 pilots and 1 flight engineer, survived the crash.

Cause 

On investigation, the cause of the crash determined to be caused by the leading edge slats kept in the retracted position throughout the climb. The leading edge slats when deployed help the aircraft take off in short distances and decrease the stall speed. Although the trailing edge flaps were lowered on Lufthansa flight 540, but slats are an essential component during the climb and descend.

The conclusion was made, thereby blaming the flight crew for not performing a proper pre-flight checklist and also accounted for the lack of warning systems, which could have alerted the flight crew. 

Aftermath 

The Captain and the First officer were both dismissed after the investigation, with the fight engineer being charged with criminal negligence, but released in 1981.

Boeing also added sufficient warning systems for the pilots, if the slats valves are not opened before takeoff.

References 

('Lufthansa Flight 540', 1st August 2020)