A United Airlines flight headed from Denver to Los Angeles was diverted last week after its windshield cracked midair, according to the National Transportation Safety Board.

United flight 1093 took off from Denver International Airport at 5:51 a.m. MDT Thursday, according to flight tracking software FlightAware . The plane was cruising above Utah when the windshield cracked, federal investigators said .

The Boeing 737-8 was safely diverted to Salt Lake City International Airport, where it landed shortly after 7:30 a.m. MDT, according to FlightAware.

NTSB officials are investigating what caused the crack. It’s not yet clear how extensive the damage was, but passengers were switched over to a new plane in Utah to finish their journey.

The flight eventually landed in Los Angeles at 1

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