The National Transportation Safety Board said that it is opening an investigation into a Delta Air Lines flight rocked by turbulence on Tuesday that sent passengers and crew to the hospital.

“The Airbus A350 was en route from Milan, Italy, when flight encountered severe turbulence on approach to its planned destination of Atlanta,” the agency said in a tweet on X, the social media platform formerly known as Twitter, on Thursday evening.

The NTSB tweet said that a preliminary report on Delta flight 175 would be expected in two to three weeks.

The Federal Aviation Administration says a total of 12 people, one more than initially reported, were hurt in the incident. That agency’s initial report says one member of the flight crew sustained serious injuries. Also, three cabin crew members and eight passengers had minor injuries, it said.

The flight was about 40 miles northeast of Hartsfield-Jackson Atlanta International Airport when the turbulence occurred, and it eventually landed safely, according to the FAA.

In a 2021 report, the NTSB found that “turbulence-related accidents are the most common type of accident involving air carriers.”

Passenger describes Delta flight

Passenger Ayọ Suber described what happened on the plane earlier this week.

The first 10 hours of the flight were fine, she said, but when they got close to Atlanta, the turbulence struck.

A woman sitting in the middle aisle flew out of her seat and the top of her head hit the overhead storage bins, said Suber.

“There was a woman who kept crying and saying she’s scared,” she added.

Suber said passengers were informed by the cockpit that medics would be standing by once the plane landed.

In a video taken by Suber, a crack can be seen on the bottom of a storage bin where a woman hit her head. After the plane landed, medics could be seen taking some passengers off the aircraft on stretchers.

“I felt like this was such a freak incident that I’m not scared to fly,” she said.