As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 3200 - DCA-BWI - THE LANDING GEAR WOULD NOT EXTEND WITH LANDING GEAR SELECTED DOWN. PERFORMED ALTERNATE GEAR EXTENSION. THE AIRCRAFT LANDED WITHOUT INCIDENT. SECURED LOOSE CONNECTOR AT LANDING GEAR INHIBIT SWITCH. LATER IN THE DAY, LANDING GEAR WOULD NOT EXTEND UPON SELECTION. REMOVED AND REPLACED THE LANDING GEAR CONTROL VALVE AND LANDING GEAR SELECTOR HANDLE. REFERENCE HNAA9791415.