What was found
DURING APPROACH, THE LANDING GEAR FAILED TO EXTEND FULLY INTO THE DOWN AND LOCKED POSITION. THE FLIGHT CREW PERFORMED A MANUAL GEAR EXTENSION IN ORDER TO ACHIEVE THE DOWN AND LOCKED POSITION. MAINTENANCE DISCOVERED THAT THE LANDING GEAR SQUAT SWITCH WAS JAMMED DUE TO SLUDGE PICKED UP DURING FLIGHT. THE MAINTENANCE TEAM CLEANED AND TESTED THE SWITCH, PERFORMED MULTIPLE GEAR RETRACTION AND EXTENSION CHECKS, AND RETURNED THE AIRCRAFT TO SERVICE WITHOUT FURTHER INCIDENT.