As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DTW - FLT 3120 - ON APPROACH, RT MAIN GEAR FAILED TO EXTEND. THE CREW PERFORMED AN ALTERNATE GEAR EXTENSION AND THE GEAR WENT TO THE DOWN AND LOCKED POSITION. MAINTENANCE REPLACED RT MLG UPLOCK ACTUATOR. SYSTEM OPERATED SATISFACTORILY. (X)