Accident Overview
On a scheduled service from Hanover Airport to Düsseldorf Airport, a twin-engine aircraft departed at 0715 local time with 19 passengers and a crew of two. The flight to Düsseldorf was uneventful at FL140 until the crew began descent at 0739 LT. After being cleared to 3,000 feet, air traffic control informed the crew of thunderstorm activity in the area and suggested an alternate route to avoid the weather. The crew declined this offer and continued the descent.
Sequence of Events
While flying in thunderstorm activity, the aircraft became unstable due to turbulence and lightning strikes near the aircraft. The electrical system failed, and the crew lost control. The airplane entered a dive, partially disintegrated in the air, and crashed in an open field approximately 2 km north of Kettwig, near Essen-Mülheim Airport. All 21 occupants were killed.
Official Findings
The probable cause was determined to be a combination of factors: the flight crew continued into an area where electrical discharge was expected, despite the possibility of avoidance; a lightning strike in significant instrument flight conditions caused total electrical supply failure, resulting in the loss of cockpit and instrument lighting and inability to use flaps and stabilizer trim; the aircraft entered largely uncontrolled flight after power failure; and the aircraft became overloaded during uncontrolled flight and disintegrated.
Contributing factors included: the crew did not agree on the flight path in the thunderstorm area; the crew were not prepared for a lightning strike; the crew may have been physically and mentally impaired for a short time after the strike; the crew could not understand each other for a short time after power failure because they wore headsets; the aircraft was in an unstabilized flight condition with nose trimmed down and flaps half way down at the time of the strike; the crew could not restore power, likely due to damage in electrical wiring; and the crew lacked sufficient means for orientation to return from predominantly uncontrolled to controlled flight.