What was found
DURING APPROACH, ATTEMPTED TO MOVE LANDING GEAR SELECTOR HANDLE TO DOWN POSITION, BUT COULD ONLY GET APPROXIMATELY 2/3 TRAVEL DOWN. CYCLED HANDLE AGAIN WITH SAME RESULT. APPROACH ABANDONED. CHECK LIST PROCEDURES WERE FOLLOWED FOR MANUAL EXTENSION. FOLLOWING EMERGENCY DECLARATION, REQUESTED A FLY-BY, A REVIEW OF ALL NORMAL AND EMERG LANDING PROCEDURES WAS CONDUCTED, A FLAT APPROACH WITH FULL FLAPS AND VREF SPEED WAS MADE. UPON TOUCH-DOWN, ROLLED TO STOP, SHUT DOWN LT ENGINE. MAINTENANCE FOUND SCREW (PN A116-2B) LODGED UNDER A LEVER ARM (PN 25-CX-1355) RESTRICTING TRAVEL OF THE ARM. AFTER REMOVING SCREW, WERE ABLE TO LOWER HANDLE ALL THE WAY DOWN. (X)