CHICAGO – An evacuation slide inflated inside a United Airlines plane as it flew from Chicago to California, filling part of the cabin and forcing the pilot to make an emergency landing in Kansas, the airline and passengers said.

Mike Schroeder said he was flying to Orange County, California, late Sunday when he heard a hiss and pop. Schroeder said he turned around and saw the plane’s evacuation slide – which would normally go outside the plane during an emergency – inflating inside the cabin.

United Airlines officials said in a statement Monday that no one aboard Flight 1463 was injured.

Passengers remained calm and took pictures of the inflated slide with their phones, Schroeder said. The Boeing 737-700 pilot announced to passengers that they would be landing at Wichita’s Mid-Continent Airport.

“When the pilot came out right after landing he said, ‘Oh golly, I’ve never seen that before,”’ Schroeder said.

Christen David, a spokeswoman for the Chicago-based airline, said the slide “accidentally deployed” and that all 96 passengers were seated when the slide inflated. The airline provided passengers hotel rooms and planned a flight Monday morning from Wichita to California.

United’s maintenance team will inspect the aircraft to find out what happened, David said.

Elizabeth Cory, a spokeswoman for the Federal Aviation Administration, said agency investigators were at the scene in Wichita, but that the investigation would take weeks. She did not have further information.