NTSB Preliminary Report: 31 Injured During Severe Turbulence on Delta Flight 56

Severe Turbulence Event

• ✈️ Delta Airlines flight 56, an Airbus A330, encountered severe turbulence on July 30th, 2025, at 37,000 ft near Creston, Wyoming.
• 🤕 31 individuals sustained injuries, including one passenger with a broken leg and fractured ribs, and two cabin crew members with serious injuries.
• 📉 Following the incident, the flight crew diverted to Minneapolis St. Paul International Airport.

Flight Crew Actions and Observations

• ☁️ The crew initially anticipated turbulence over mountains east of Salt Lake City but experienced smoother conditions until flight level 300.
• ⚠️ At flight level 350, the seat belt sign was turned off despite some weather buildups, as the electronic flight bag showed predicted turbulence in the green.
• 🔄 After accepting a left turn from air traffic control to deviate from weather, the aircraft experienced an overspeed event, an updraft, and a subsequent abrupt descent, repeating a climb-descent cycle.
• 🛬 The flight crew initiated an all-attitude absent recovery strategy and eventually re-engaged the autopilot.

Aircraft and Passenger Data

• 📊 Preliminary FDR data revealed the upset lasted approximately two and a half minutes, with significant oscillations in vertical acceleration, pitch, roll, and airspeed.
• ⛈️ A convective significant meteorological information (SIGMET) was in effect, warning of thunderstorms with cloud tops above flight level 4550.
• 🧑‍⚕️ A passenger who was a physician assistant aided the cabin crew with triage after the event.
• ⛽ The flight crew reviewed overweight landing performance data and elected to divert to Minneapolis.

Post-Landing Procedures

• 🚨 Upon landing, airport rescue, firefighting, medical, and maintenance personnel met the aircraft.
• 🔥 The crew notified ground personnel about hot right main landing gear brakes, with both sides eventually becoming warm.
• ✈️ The aircraft sustained minor damage to interior components.