'Thought we were going to die': United Airlines jet makes emergency landing after flames break out in engine

The Federal Aviation Administration is looking into a mechanical issue on a United Airlines flight that caused flames to shoot from the rear of an engine minutes after takeoff Monday evening.

The 21-year-old Boeing 737 departed from Houston's Bush International Airport and was headed to Fort Myers with 167 passengers onboard when the captain turned the plane around and made an emergency landing back in Houston.

Passengers told ABC News that flames began shooting from an engine on the left side of the aircraft 15 minutes into the flight to Fort Myers, Florida.

David Gruninger took a video showing flames engulfing the engine as the plane began to shake.

"Panic set in with a lot of people," Gruninger told ABC News. "A lot of the people around me were screaming and crying."

According to a recording of air traffic control transmissions provided by LiveATC.net, the pilot radioed in the midair emergency, saying, "Got 167 souls on board ... we had engine limited surge and stall on the left engine."

Such engine compressor stalls, which occur a few times a year, cause excess fuel to burn off, according to aviation experts.

"It was our left engine, our number one engine, that was surging when we were climbing through about 10,000 (feet), and flight attendants saw momentary flames back there," a pilot said, according to the recorded traffic control transmissions.

The plane was forced to return to Houston.

United Airlines said in a statement that the incident was "due to an engine issue. The flight landed safely and passengers deplaned normally."

But passenger Elliott Trexler told ABC News there was nothing normal about the flight.

"The cabin was dark but it suddenly was illuminated with red, orange and yellow colors. The engine was totally engulfed in flames," Trexler said.

Once back on the ground, a shaken Trexler told ABC Houston station KTRK he started composing a goodbye message to his wife.

"I think it's fair to say we all thought we were going to die," said Trexler, adding, "The plane was rocking back and forth a lot."