(Reuters) – A Southwest Airlines Co flight made an emergency landing in Cleveland at about 11 a.m. EDT (1500 GMT) on Wednesday after a window cracked in flight, airline officials and the Federal Aviation Administration said.

The cause of the crack was not immediately known.

A passenger on a Southwest flight died after an engine ripped apart in flight on April 17, shattering a window on the 737. It was the first U.S. airline passenger fatality since 2009.

In Wednesday’s incident, Southwest Flight 957 was traveling from Chicago Midway International Airport to Newark Liberty International Airport before the crew diverted the plane to Cleveland-Hopkins International Airport to inspect a layer of a windowpane, said Southwest spokesman Brian Parrish.

No passengers were injured, said FAA spokesman Tony Molinaro, who added that the organization was investigating the incident.

Reuters