Fifty people were injured by “a strong shake” that came during a Monday flight from Sydney to Auckland, New Zealand, prompting an investigation from Chilean airline LATAM and a large response from emergency services.

Passengers, speaking to local media, described seeing people being thrown to the ceiling and then falling to the floor as those on board felt a sudden rollercoaster-like drop — as if the plane were taking a nosedive — before the plane quickly leveled.

A spokesperson for LATAM in an earlier statement described the incident as a “technical event” during the Auckland-bound flight aboard the Boeing 787-9 Dreamliner carrying 263 passengers and nine flight and cabin crew members. Flight 800 was stopping in Auckland before heading to its final destination of Santiago, Chile.

The airline confirmed in a statement to The Washington Post that 10 passengers and three cabin crew members were taken to Middlemore Hospital “to confirm their health condition” after the flight made its scheduled landing at Auckland International Airport on Monday afternoon. Separately, Auckland emergency services assessed and treated about 50 people, sending a dozen people to the hospital, including one in serious condition.

The airline said it “deeply regrets any inconvenience and discomfort this situation may have caused its passengers.”

A spokesperson for Boeing said, “We are working to gather more information about the flight and will provide any support needed by our customer.”

The Hato Hone St. John ambulance service said in a statement that its crews responded to an incident at Auckland International Airport involving an inbound aircraft Monday afternoon local time. After seven ambulances and other vehicles and teams arrived at the scene, they “assessed and treated approximately 50 patients,” including one in serious condition and the remainder in moderate to minor condition, the service said.

A passenger on board told Radio New Zealand that the flight was going smoothly until about two-thirds of the way into the roughly three-hour journey to New Zealand, when the plane “just dropped.”

The passenger, Brian Jokat, told the outlet that several passengers were thrown up to the ceiling of the plane, with some breaking parts of the cabin on impact and others injuring themselves when they hit the floor.

“Then people just started screaming. I felt the plane take a nosedive — it felt like it was at the top of a roller coaster, and then it flattened out again,” Jokat said. The entire incident lasted only “split seconds,” he said.

Another passenger, Priscilla Waller-Subritzky, told the New Zealand Herald that the plane lost altitude and that “a number of passengers and crew were thrown into the roof of the plane.” She said “the crew were injured so couldn’t help” the passengers who were hurt.

LATAM canceled the final leg of Flight 800, saying a new Santiago-bound flight is scheduled for Tuesday, departing from Auckland at 8 p.m. local time. The airline said it is covering food and accommodation for affected passengers.