What happened
On December 16, 2019, at 21:34 local time, an Airbus A330-220, registration EC-LQO, was performing a descent toward Adolfo Suárez Madrid-Barajas Airport as part of a regular commercial flight from Gran Canaria. While flying near the RILKO waypoint at approximately 10,500 feet, the aircraft encountered a sudden and violent patch of clear-air turbulence.
At the time of the event, the flight crew had already announced the cabin was being secured for approach, and the passenger seatbelt sign was illuminated. The turbulence was so abrupt that one cabin crew member was thrown, resulting in a serious injury involving a fractured tibia and fibula. The remaining 10 crew members and 163 passengers were uninjured. The aircraft landed safely at Madrid-Barajas without any structural damage.
The investigation
The CIAIAC investigation examined the meteorological conditions, flight data, and crew performance. Investigators analyzed the aircraft's flight data recorder (FDR) and direct access recorder (DAR), which captured a vertical acceleration of 2.062 g during the encounter.
Meteorological analysis revealed that the aircraft was positioned between two high-altitude jet streams, a configuration highly conducive to severe turbulence. While the flight dispatch documentation did not explicitly warn of turbulence in the specific accident area, the crew had received ATIS information (XRAY and Z) which warned of moderate turbulence and icing at the RILCO waypoint at 11,000 feet. The investigation also reviewed the actions of the crew following the event, noting that while the turbulence was not reported to air traffic control immediately due to high cockpit workload during the approach, the crew effectively coordinated medical assistance upon landing.
Findings
- The primary cause of the accident was the aircraft encountering turbulence of an intensity greater than predicted during the approach to Madrid-Barajas.
- Although the ATIS provided a warning of moderate turbulence, the aircraft's weather radar was unable to detect the specific pocket of clear-air turbulence.
- No reports of turbulence were received from preceding aircraft in the immediate vicinity at the time of the event.
- The crew prioritized aircraft control during the high-workload approach phase, which delayed the reporting of the turbulence and the injury to air traffic services.