As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD-PHL - FLT NR 6237 - DURING CLIMB-OUT, RETURNED TO IAD DUE TO THE RED GEAR SELECTOR HANDLE REMAINED ILLUMINATED AFTER GEAR WAS UP AND LOCKED AFTER TAKEOFF. AIRCRAFT LANDED AT IAD WITH NO FURTHER INCIDENTS. MAINTENANCE REPLACED THE RIGHT STANDBY UPLOCK MICRO-SWITCH. (M)