Small Aircraft
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 180; Flight Crew Total 21400; Flight Crew Type 30
Situational Awareness
Ground Event / Encounter Ground Strike - Aircraft; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
Flight Crew Regained Aircraft Control
Aircraft; Procedure
During the landing rollout on runway XX at ZZZ; the [tailwheel biplane] I was operating abruptly departed from the paved runway surface onto the grass adjacent the runway. The wheel landing and initial rollout were uneventful and smooth. However; immediately after the tail wheel touched down onto the runway surface the aircraft swerved uncontrollably to the left. I reacted immediately with full right rudder trying to prevent the aircraft from departing the paved surface.As the aircraft began to exit the runway; 'at approximately 25 knots;' the lower right bow wing and lower right aileron scrapped the runway surface; damaging the wings outer edge. I added power to regain control of the aircraft approximately 10 ft left of the runway paved edge in the grass adjacent the runway. I continued maneuvering the aircraft in the grass for approximately 300 feet fortunately missing runway signs; runway lighting; and passing over a drainage ditch. I returned to the runway paved surface shortly thereafter. I taxied the aircraft back to the hangar under its own power. The weather at the field was clear; greater than 10 miles visibility; temp 73 degrees; and winds light and variable.
Pilot reported they do not know what caused the aircraft to veer left.
GA pilot reported runway excursion after landing; causing damage to the aircraft.