DCA24LA174

On April 26, 2024, at 1330 eastern daylight time, Delta Air Lines flight 1044 encountered turbulence during descent into Hartsfield/Jackson Atlanta International Airport (ATL), Atlanta, Georgia. The flight was a regularly scheduled passenger flight from John Wayne/Orange County Airport (SNA), Santa Ana, California to ATL. As a result of the turbulence, one flight attendant sustained serious injuries. The airplane was not damaged, and the flight continued to ATL without further incident. The flight crew reported that the decent had initially been relatively smooth. As the airplane descended through 10,000 ft with the seatbelt sign on, the captain alerted the cabin crew with a double chime, which was the signal for them to complete their final walkthrough and prepare the cabin for arrival. Three of the four flight attendants began to get up in the aft galley to perform the final descent checks. Shortly thereafter, the airplane flew through what was described by the flight crew to be a very small cumulus cloud and encountered one jolt of moderate turbulence. During the turbulence encounter, two of the flight attendants in the aft galley stated they were thrown into the air, and one landed on her left foot, resulting in an injury that was later diagnosed as a fracture. The cabin crew notified the flight deck of the injury, secured the injured flight attendant in a jumpseat and applied ice to her foot. The captain declared a medical emergency with air traffic control and asked for medical personnel to meet the flight at the gate. The flight was given priority for landing at ATL. A post-accident review of weather records revealed that were no convective significant meteorological information (SIGMETs) or airman’s meteorological information (AIRMETs) regarding turbulence in effect at the time and location of the accident. Cloud bases for broken and overcast layers in the area were reported between 7,000 and 9,000 ft respectively, with no precipitation present. A doppler radar derived wind profile for Atlanta showed the wind at 11,000 ft was from about 270° at 15 knots. It shifted to about 190° at 10 knots at 9,000 ft. Eddy dissipation rate (EDR) is a universal measurement of turbulence rate, based on estimated vertical wind velocity, or aircraft vertical acceleration. Some airplanes can record and broadcast EDR values. EDR values were not available for the accident airplane, however records from several other airplanes arriving at ATL from the southwest near the time and location of the accident revealed that they had experienced peak EDR values of 0.2 to 0.3. These values are aircraft independent, and the relationship between the EDR value and the perception of turbulence is a function of aircraft type, and the mass, altitude, configuration and airspeed of the aircraft. The World Meteorological Organization provides the following table for EDR values for a medium-size transport category airplane under typical en-route conditions: Table 1. Eddydissipation rate values for a medium-size transport category airplane. (Source: World Meteorological Organization) Based on the flight crew statements and the EDR data from other airplanes operating in the vicinity, it is likely that the accident airplane experienced light to moderate turbulence. The flight crew’s reporting of entering a cumulus cloud when the turbulence occurred, along with visible satellite imagery for the area showing cumulus cloud formations, suggests the turbulence was most likely convectively induced.