What happened
A CASA 212 was operating a scheduled, domestic, passenger commuter flight under 14 CFR Part 135 from San Juan, Puerto Rico, to Mayaguez, Puerto Rico. The flight was conducted under VFR conditions with a flight plan filed. At the time of the incident, the prospective captain was operating the aircraft from the left seat while undergoing an initial operating experience check ride from an authorized check airman.
Upon arrival at the destination airport, the aircraft was in its landing rollout phase when the nosewheel developed a heavy vibration. This vibration caused the airplane to veer off the runway to the right, where it subsequently collided with a sign. There was no damage sustained by the aircraft, and the flightcrew and 16 passengers were not injured.