What was found
LT & RT MAIN GEAR FAILED TO RETRACT AFTER TAKEOFF. HYD PRESSURE NORMAL. GEAR INHIBIT SWITCH WAS IN NORMAL. GEAR EXTENDED DURING ALTERNATE GEAR EXTENSION CHECKLIST. LANDING UNEVENTFUL. COMPLIED WITH FIM TASK 32-00-00-810-809. OPS TEST WAS SATISFACTORY. REPLACED SECONDARY MLG SELECTOR VALVE FILTERS IAW AMM TASKS 29-21-06-000-802 AND 29-21-06-400-802. NO DEFECTS NOTED. RETURNED TO SERVICE.