What happened
On September 9, 2019, an Airbus A319-112 was performing a descent from FL320 to FL230 while en route from Lamezia Terme, Italy, to Berlin Tegel. As the aircraft approached a cloud layer, the crew activated the weather radar. At approximately 16:31 UTC, while descending through FL233, the aircraft encountered severe turbulence. The event caused a negative vertical acceleration of approximately -0.6 g, briefly interrupting the descent and causing the aircraft to climb at a rate of 7 and 700 ft/min.
During the turbulence, the wind speed increased by roughly 15 knots and the wind direction shifted by 20 degrees. The impact caused several injuries within the cabin: two flight attendants struck their heads on the ceiling, one flight attendant sustained a finger injury, and one passenger was thrown against the ceiling. In total, seven persons were lightly injured and one person was seriously injured (the latter requiring hospitalization for more than 48 hours). Following the event, the pilot requested medical assistance upon landing and informed air traffic control that the aircraft could not maintain the prescribed descent rate and speed due to the weather conditions.
The investigation
The BFU examined the flight data recorder (FDR) and cockpit voice recorder (CVR), finding the FDR data was recoverable through interpolation during a brief period of erroneous recording. The investigation also analyzed radar data from air traffic control, which ruled out wake turbulence from other aircraft as a cause. The BFU reviewed the aircraft's maintenance logs, which showed a subsequent turbulence inspection was performed with no defects found. Additionally, the investigation involved a meteorological analysis of the weather conditions, including the use of the Eddy Dissipation Parameter (EDP) to evaluate the accuracy of turbulence forecasts provided by the German Meteorological Service (DWD).