SACRAMENTO, Calif. (AP) — A Montana man accused of trying to carry four loaded handguns and a knife onto a flight at Sacramento International Airport has pleaded not guilty to federal charges.

Forty-five-year-old Harold Waller entered his plea Monday to five counts of attempting to get on an aircraft with a concealed, dangerous weapon.

Authorities say Waller was going through a security checkpoint on March 22 when agents found one gun on him and the other weapons packed in his carry-on luggage. Waller was trying to get on a US Airways flight to Phoenix, then on to Anchorage.

Waller’s mother, Helen Waller of Circle, Mont., previously told The Associated Press that her son is mentally ill and had been receiving treatment for depression at a Sacramento clinic.