As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BWI - FLT 539 - EN ROUTE BWI-ORD, MAIN LANDING GEAR WOULD NOT RETRACT. RETURNED BWI AND LANDED WITHOUT FURTHER INCIDENT. RE-STOWED MAIN LANDING GEAR DOOR BYPASS HANDLE. INSPECTED MAIN LANDING GEAR AND DOORS. NO DEFECTS NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)