Accident Sequence
The aircraft was substantially damaged when the nose wheel collapsed as the pilot attempted to taxi back onto the runway after departing the pavement during landing rollout on runway 3. The pilot reported that the landing touchdown was on the centerline, but shortly afterward the aircraft encountered an "overwhelming" wind gust which caused it to weathervane to the left. The pilot applied full right rudder and differential right braking, which was effective in stopping the aircraft's drift. However, a second "much stronger and sustained" gust caused the aircraft to "veer strongly to the left." The pilot's subsequent efforts to maintain directional control through differential braking and differential engine thrust were insufficient to keep the aircraft from departing the runway pavement. The aircraft came to rest in the soft grass adjacent to the runway.
Nose Wheel Collapse
The pilot attempted to taxi back onto the runway. However, the nose wheel contacted the edge of the pavement and collapsed. Distinct ruts were observed in the soft turf adjacent to the left side of the runway. The nose wheel tire track approached the edge of the pavement at approximately a 20-degree angle and terminated at the edge of the runway. The track was approximately eight inches deep relative to the level of the runway pavement.
Aircraft and Operational Information
The nose wheel steering was inoperative and had been deferred in accordance with the operator's Minimum Equipment List (MEL). In that situation, the nose wheel was in the "free castor mode." The MEL states that directional control is to be maintained by using brakes and differential power. The published maximum demonstrated crosswind component for the aircraft was 22 knots. The operator did not impose a crosswind component limitation on operations in general or on operations with the nose wheel steering inoperative under the MEL.
Weather Conditions
Surface winds provided to the flight crew by the control tower were 310 degrees at 23 knots, gusting to 30 knots.