What was found
DURING FLIGHT, LT MLG FAILED TO EXTEND BUT TRAILED, DISCONNECTED FROM HYD SYS. PILOT WAS ABLE TO ROCK LT MLG INTO DOWN AND LOCKED POSITION, MADE SAFE LANDING. DETERMINED, ACTUATOR BODY HAD CRACKED THROUGH FWD ATTACH HOLE, HALF THROUGH AFT ATTACH HOLE, WHICH CAUSED ACT TO SEPARATE WHEN HYD PRESS WAS APPLIED THUS SEPARATING ACTUATOR PISTON GEAR SHAFT FROM SECTOR GEAR MOUNTED TO PIVOT. ACT ATTACH BOLTS WERE FOUND TIGHT, SAFETY WIRE UNDISTURBED. ACTUATOR BODY WAS REPLACED, ACTUATOR WAS RESEALED, REASSEMBLED, REINSTALLED AND TORQUED IAW SRM. SUSPECT FAILURE OF ACTUATOR BODY MAY BE SHEAR STRESS ON ACTUATOR ATTACH BOLT HOLES DUE TO HIGH NR OF GEAR CYCLES. INSP OF RT GEAR ACT BODY, NO CRACKS OR DEFECTS. (K)