Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Private
Flight Crew Last 90 Days 41; Flight Crew Total 541; Flight Crew Type 18
Training / Qualification
Aircraft Equipment Problem Critical; Ground Event / Encounter Loss Of Aircraft Control; Ground Event / Encounter Object; Ground Excursion Runway
General Maintenance Action
Aircraft
I was completing the last leg of a 2 day cross country flight with a new airplane. The approach and flare were both exactly on speed and well stabilized. I touched down very smoothly on the main wheels and as the nose came down during the rollout; the aircraft started to veer right. I applied full left rudder and maximum braking force on the left brake and was unable to keep the aircraft on the runway. It acted like the nose wheel was locked and unable to turn left or right. When I realized that [I] was not going to be able to keep the aircraft on the runway; and a runway sign was directly in front of me; I applied full right brake to try and avoid the sign. Unfortunately; the left wing hit the sign and caused damage to the leading edge of the left wing and left side of the cowling.During the 5 leg trip I had no trouble with steering the aircraft during takeoff or landing. Prior to the last leg of the trip; I dropped off a passenger and his baggage; so was significantly lighter than any other point in the trip. I suspect that the nose strut had been excessively serviced with nitrogen causing it to stay fully extended at this lighter weight. With it fully extended; the internal centering cam in the strut locks the wheel straight.
General aviation pilot  lost control during landing roll and hit a runway sign. Reporter suspected over serviced nose strut locked the nose wheel.