What was found
LANDING GEAR FAILED TO RETRACT FULLY IN-FLIGHT. ISOLATED ACTUATORS AND FOUND LEFT MAIN GEAR ACTUATOR BYPASSING (AUDIBLE) FLUD/PRESSURE. DISASSEMBLED ACTUATOR. FOUND DAMAGED AND APPARENTLY INCORRECT (UNDERSIZE) O-RING. INSTALLED ON ACTUATOR PISTON. SUSPECT INCORRECT O-RING INSTALLED AT MANUFACTURER (CLEVELAND) DURING ASSEMBLY. RECOMMEND ACTUATOR AND AIRCRAFT MANUFACTURERS INSPECT ALL FACTORY STOCK AND SPARES FOR PROPER O-RING INSTALLATION.