What was found
AFTER TAKEOFF, WHEN CREW SELECTED GEAR RETRACTION, A "GEAR DISAGREE" AMBER CAS MSG POSTED FOLLOWED BY A "PROX SENSOR FAULT" CYAN CAS MSG. CREW RESET GEAR TO DOWN AND LOCKED AND REQUESTED A TOWER FLY-BY TO ENSURE GEAR WAS IN FACT DOWN AND LOCKED. ATC PERSONNEL DECLARED AN IFE. ACFT LANDED WITHOUT INCIDENT. MX PERSONNEL PERFORMED MEL PROCEDURE. ACFT MOVED TO MX BASE WHERE THE RT MLG ACTUATOR WAS REPLACED. SUSPECT INTERNAL SWITCH AT FAULT. MX ENGINEERING SUSPECTS R MLG ACT DID NOT MOVE ON RETRACTION.