Merlin III
Air Traffic Control Fully Certified; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 15; Flight Crew Total 10839; Flight Crew Type 9180
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Object; Ground Event / Encounter Weather / Turbulence; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
Aircraft Aircraft Damaged; Flight Crew Regained Aircraft Control
Human Factors; Weather; Aircraft
Upon landing; nose wheel landing gear malfunctioned and veered hard left uncontrollably. Corrective action was hard right breaking action and hard reverse.  Control was gained but only after one prop blade struck sign on edge of runway. As exiting runway; steering was engaged only to realize the steering was inoperable and was unable to completely exit the runway. A tug was requested to assist; then taxi to repair station on field in which repairs could be made. Conditions were light rain; wind and wet pavement. After investigations; a shuttle valve in nose wheel steering was inoperable causing the action. Nose wheel steering was operable at departure airport.
Pilot flying Merlin IIIB aircraft reported loss of Nose Wheel Steering control during landing rollout. Post flight inspection revealed shuttle valve in Nose Wheel Steering was inoperable.