As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON GEAR EXTENSION, THE MAIN LANDING GEAR DID NOT EXTEND. CREW ATTEMPTED A SECOND TIME AND GEAR FULLY EXTENDED. CREW DECLARED AN EMERGENCY AND LANDED WITHOUT INCIDENT. REMOVED AND REPLACED THE RT MLG UP LOCK BOX ASSY IAW EMB MM CH 32-33-10. OPERATIONAL AND FUNCTIONAL CHECKS GOOD .