A United Airlines flight from Denver to Billings that was buffeted by severe turbulence that left five people injured Monday is under investigation by the National Transportation Safety Board.
Earlier in the week, the NTSB was gathering information to decide whether it would open an investigation. The federal agency weighs many factors in deciding which air incidents to investigate, said Terry Williams, an NTSB public affairs officer.
"We look at injury; that's one of our thresholds," he said. "We look at safety concerns."
United Airlines Flight 1676 was struck by severe turbulence on Monday afternoon near Sheridan, Wyo. The choppy air was rough enough that it caused five injuries aboard the aircraft, including three flight attendants. The plane landed safely at Billings Logan International Airport.
Williams confirmed that the NTSB secured the flight data recorder and voice recorder from the flight shortly after it landed.
Typically in an investigation into an incident like the one that occurred on Monday, the NTSB interviews crew members and passengers and they comb through the data collected on the recorders, Williams said.