The L.A. City Attorney's Office has filed three charges against Henrie -- carrying a loaded firearm, carrying a concealed firearm and possessing a weapon in a sterile area of the airport.

We broke the story ... Henrie was busted earlier this month after TSA agents discovered he had a loaded gun on him. He was taken into custody shortly afterward. The weapon was an M&P Shield 9mm pistol.

Our cameras spoke with David after his release and he told us the whole thing was a mistake, and the gun was totally legal. He also praised cops for their handling of the incident. In a statement, he said, "More than anything I am humiliated and embarrassed that this even happened."

If convicted, he faces a maximum of one year behind bars.