AVIATION/ RECALLING KLM CITYHOPPER FL431

A rare and disasterous event took place 29 years ago today, when KLM CITYHOPPER Flight 431 crashed near Moerdijk, Netherlands. On that date, Flight 431 was on Scheduled International Fokker F28 Service from Rotterdam, Netherlands, to Hamburg, Germany, with a stop in Eindhoven, Netherlands. About 45 minutes before departure, the flight crew underwent a weather briefing. They were warned about an area of thunderstorms with 3/8 cumulonimbus at 1200 feet. At 5:04pm, the Fokker departed Rotterdam with 13 passengers and 4 crew members onboard. At 5:09pm, the crew noted heavy rain in thunderstorms on the weather avoidance radar and received clearance to avoid the area. At 5:12pm, Flight 431 encounterd and entered a tornado, while flying through the clouds, which resulted in what is probably some of the worst and extreme turbulence ever recorded by an aircraft. The stress resulted in loads increasing to +6.8g and -3.2g, respectively, for a total loading of 10g. The right wing separated, followed by an inflight breakup. The Fokker crashed out of control from 3000ft, near Moerdijk, killing all 17 onboard. The crash site was 15 miles S/SE of Rotterdam. The disintegrating airliner was seen exiting cloud cover by ground witnesses. A police officer first photographed the tornado, then smoke from the burning plane a few minutes later. An investigation concluded that a sharp increase in altitude registered on the altimeter was not a change in altitude, rather a pressure drop associated with the tornado.