Travelers on a Delta connection flight from Rapid City, S.D. to Salt Lake City experienced an unusual delay Wednesday morning.

Police arrested the flight’s pilot Russel Duszak, 38, under the suspicion that he was trying to fly under the influence of alcohol. SkyWest is a regional airline that was operating for Delta at the time, CBS reports.

The SkyWest 4574 flight, which had 45 people, was reportedly Duszak’s first flight of the day.

 

TSA officers said Duszak smelled of alcohol, according to The Rapid City Police Department’s Facebook post. Authorities were subsequently called in to investigate. Police later determined the pilot’s blood-alcohol content was over .04—the maximum blood-alcohol content a pilot can have while operating a plane.

ABC News reports that Duszak has been removed from his flying duties and has been placed on administrative leave. He was released from jail after paying a $300 bond.

In a tweet, Karl Jegeris, the police chief of the Rapid City Police Department, wrote, “The system worked the way it is designed to ensure passengers safety was not compromised.”

SkyWest apologized for the delay and blamed it on a “crew member issue,” according to CBS, although the airline is reportedly still investigating the delay.

Fortune has reached out to SkyWest and will update the story if we receive a response.