As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT OF KIAD, GEAR WENT FROM DOWN AND LOCKED TO UP AND LOCKED WITHOUT A TRANSIT INDICATION. CREW THEN RETURNED A/C TO KIAD FOR MAINTENANCE TO TROUBLESHOOT. MAINTENANCE INSPECTED AND FOUND THAT THE RIGHT MLG UPLOCK NR 2 PROX SWITCH BAD. REMOVED AND REPLACED AND PERFORMED OPS CHECK OF LANDING GEAR GOOD.