Passengers on a Southwest Airlines flight from from Albany to Chicago endured a four-hour delay Monday after the co-pilot of the plane was arrested for packing a loaded handgun. 

CBS DFW reports that the Southwest co-pilot was stopped by Transportation Security Administration agents who found a .380-caliber gun in his carry-on bag during a routine screening Monday morning.

Albany County Sheriff’s officials tell the Dallas Morning News the man told them he forgot that the gun was in his bag. He had previously piloted a flight from New Orleans to Albany on Sunday evening, but his bags weren’t screened before that trip, he said.

Upon finding the gun, which was loaded with six bullets, the TSA agent contacted the Sheriff’s Deputy on duty, who confiscated the weapon and arrested the co-pilot.

“This incident highlights the importance of what TSA and its dedicated security officers do each and every day in protecting the flying public,” Bart R. Johnson, the TSA’s Upstate New York federal security director, said in a statement.

Under TSA rules, firearms, parts, and ammunition are not permitted in carry-on bags. However, they can be packed in checked bags if they are unloaded, locked in a hard-sided container, and declared to the airline.

Southwest did not respond to the Dallas Morning News’ request for comment. Consumerist has reached out to the airline, and will update this post when we hear back.

The pilot was charged with misdemeanor criminal possession of a weapon, the Dallas Morning News reports, adding that the was released after posting a $200 bail.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.