NLM CityHopper Flight 431


NLM CityHopper Flight 431 refers to a Fokker F-28-4000, registration PH-CHI, that was due to operate an international scheduled Rotterdam–Eindhoven–Hamburg passenger service. On 6 October 1981, the aircraft encountered severe weather on the first leg, minutes after taking off from Rotterdam Airport, and crashed south-southeast of Rotterdam. All 17 occupants of the aircraft – 13 passengers and crew of 4 – perished in the accident.

Aircraft

The aircraft involved in the accident was a Fokker F28-4000, registration PH-CHI, that was built in 1979 with c/n 11141. At the time of the accident the airframe had accumulated 4,485 flight hours and 5,997 cycles.

Description of the accident

During the weather briefing 44 minutes before takeoff, the crew was apprised to an area of strong thunderstorms with 3/8 sky coverage of cumulonimbus at a base of, south-southwest winds strong, and visibility at Rotterdam Airport. The aircraft took off at 5:04 p.m. CET from RTM. The crew noted heavy rain in thunderstorms on the airplane's weather avoidance radar at 5:09 p.m., receiving clearance to avoid the area. At 5:12 p.m. the aircraft entered a tornado while flying through clouds. The weather system the aircraft entered into was apparently the same "tornado-like" system that Zeeland locals described as being responsible for considerable property damage. Meteorologically, these vortices are indeed tornadoes, and the disintegrating airliner was seen exiting cloud cover. 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.
Stresses experienced by the airframe owing to severe turbulence resulted in loads of +6.8 g and −3.2 g causing the starboard wing to detach. The Fellowship was designed for a maximum G-load of up to 4 g. The aircraft spun down into the ground from, crashing some from a Shell chemical plant on the southeastern outskirts of Moerdijk. All 17 occupants of the aircraft perished in the accident.. While observing the unfolding incident from the ground, a firefighter suffered a fatal cardiac arrest.