BILLINGS, Mont. >>  Federal authorities are looking into severe turbulence that triggered “pandemonium” aboard a United Airlines flight into Billings, Mont., and sent five people to hospitals with injuries.

Three crew members and two passengers were injured, United Airlines spokesman Luke Punzenberger told The Denver Post. The captain declared a medical emergency as the Boeing 737 approached Billings, Federal Aviation Administration spokesman Ian Gregor told the Billings Gazette.

Flight 1676 left Denver International Airport around noon and landed without incident just before 1:30 p.m. at Billings Logan International Airport, Gregor and the airline said.

One flight attendant remained in the hospital late Monday, Punzenberger said. He says 114 passengers and five crew members were aboard.

Passenger Ejay Old Bull of Billings says drinks had just been served and passengers were moving around the cabin when flight 1676 began to lurch violently about 55 minutes after it left Denver.

Old Bull says he watched the unrestrained woman next to him crash into the luggage bin overhead and briefly lose consciousness, while a crew member got bounced around in the galley just behind his seat.

Passenger Joe Frank, 20, told The Denver Post in an email that the plane dropped violently and he heard a loud bang. He said a baby was propelled out of a parent’s arms and landed in a seat nearby, but the infant didn’t appear to be hurt.

“I didn’t have my seat belt on, so I hit my head pretty hard but what hurts is my lower back and hips,” he told the newspaper. He said he was heading from a visit to Texas back home to Billings.

National Transportation Safety Board spokesman Terry Williams says authorities are looking into the severity of the injuries and whether the Boeing 737 involved suffered any damage.