Primary finding
Probable cause
an inadvertent encounter with clear air turbulence.
Investigator assessment
Analysis narrative
On February 24, 2018, at about 1258 central standard time, Delta Air Lines flight 2023, an Airbus A330-323, N817NW, encountered turbulence while descending enroute to Minneapolis–Saint Paul International Airport (MSP), Minneapolis, Minnesota. Of the 298 passengers and crew onboard, one flight attendant sustained serious injuries and two flight attendants sustained minor injuries. The airplane was not damaged. The flight was operating under 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from Orlando International Airport (MCO), Orlando, Florida, to MSP. According to the flight crew, air traffic control indicated that there were no pilot reports of significant turbulence from preceding airplanes along their descent route. However, the flight encountered severe turbulence as it was descending through about flight level 200. The seatbelt sign was illuminated. When the turbulence was encountered, the flight attendants were beginning their cabin preparations for landing and the flight attendants were thrown to the floor. One flight attendant was thrown against the 4R door, striking her head and back. After landing, the injured flight attendant was transported to the hospital and diagnosed with a fractured vertebrae.