ATLANTA — Rock guitarist Rick Derringer told a federal air marshal that he keeps his gun with him on commercial airline flights 30 to 50 times a year, and was only detained last month at Atlanta’s airport near the end of a trip to Mexico, authorities said.

Found with a loaded gun in his carry-on bag after stepping off a Delta Air Lines flight from Cancun, Mexico, he now faces a criminal charge in Atlanta, court records show.

Derringer told the air marshal that having his gun with him has never posed a problem until this year, when it was found at Hartsfield-Jackson Atlanta International Airport on his return trip from Mexico, a court affidavit states.

“Derringer explained that he was aware that his pistol was in his carry-on bag but he thought that it was acceptable to carry a pistol on an airplane,” according to the criminal complaint filed this week in U.S. District Court in Atlanta.

He was charged this week with unlawfully entering the Atlanta airport’s secure area Jan. 9.

The Kel-Tec pistol with six rounds of ammunition was found during a search of Derringer’s tan bag after his flight had landed in Atlanta authorities said. Since he had arrived on an international flight, he was being re-checked by security in order to continue on to Sarasota when the weapon was found, the court records indicate.

Derringer meant no harm, and will work with the government to clear his name, his manager Kenn Moutenot said in a statement.

He thought he was permitted to have the gun because he has a license to carry one, Moutenot said in the statement given to the AP and WSB-TV in Atlanta.

Derringer has a Florida pistol permit that’s valid through 2020, the court records indicate. But numerous signs are displayed in the Atlanta airport warning passengers that they are not allowed to carry guns on airplanes.

On Jan. 5, Derringer had been processed through the Sarasota, Florida, airport by its screeners and then flew to Atlanta and on to Cancun, records indicate.

“The person who missed this in the screening was terminated,” said Rick Piccolo, president and CEO of Sarasota-Bradenton International Airport. “This is one where it got through, and the person did not do what they’re supposed to do or trained to do.”

“Unfortunately in this business you have to be right 100 per cent of time,” Piccolo added.

Derringer told the air marshal during questioning in Atlanta that he had also passed through security in Cancun and was able to board the Delta flight.

Passenger carry-on bags are checked at that airport, and guns are not allowed, said Adolfo Castro, the director of Grupo Aeropuertos del Sureste, which runs the Cancun airport.

Castro said he didn’t know how Derringer could have boarded a flight with a weapon, adding “this will have to be investigated.”

“I am very surprised that he would say he flies 30 times per year with a gun,” Castro said.

A Transportation Security Administration spokesman had no immediate comment but said he would check on the matter. Delta Air Lines representatives had not yet returned a message late Friday.

Derringer sang the 1965 hit “Hang on Sloopy” with The McCoys and later recorded “Rock and Roll, Hoochie Koo.”