On April 30, 2006, about 1600 mountain daylight time, a Cessna 172N, N739AJ, collided with a sign while taxiing to parking at the Billings Logan International Airport, Billings, Montana. The airplane, which was registered to and operated by the pilot, sustained substantial damage. The private pilot and his passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the 14 CFR Part 91 personal cross country flight. The flight originated in Lewiston, Idaho, about 1310, and the intended destination was Billings. According to the pilot, as he was looking to his right to taxi into a parking place on the ramp, the airplane's left wing struck a sign pole. His passenger tried to warn him about the sign, and he applied the brakes, but was unable to stop before contacting the sign. An FAA inspector examined the airplane and reported that the left wing sustained structural damage.