As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF AT IAD GEAR RED LIGHT STAYED ON WHEN HANDLE WAS PLACED IN UP POSITION. GEAR WAS RETURNED TO DOWN AND LOCKED. RETURNED TO IAD. REPLACED BENT GROUND SENSING CONTROL ROD AND SERVICED NLG STRUT. OPS CK OK. THREE DAYS LATER SAME PROBLEM REOCCURRED. NLG DOWN POS SENSOR RPL. NO FURTHER INCIDENT.