As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GSO - FLT 1658 - ON CLIMB-OUT, AFTER GEAR RETRACTION, THE LEFT MAIN LANDING GEAR RED UNSAFE LIGHT REMAINED ILLUMINATED. CREW RECYCLED GEAR WITH NO HELP. FLIGHT RETURNED TO FIELD AT GSO AND LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. MAINTENANCE FOUND THE LEFT MLG UPLOCK PROXIMITY SWITCH WITH HIGH RESISTANCE. REMOVED AND REPLACED THE LEFT MLG UPLOCK PROXIMITY SWITCH PER MM 32-61-21. OPERATIONAL CHECK GOOD. (M)