What was found
ALL 3 MLG WOULD NOT RETRACT AFTER TAKEOFF. 3 GREEN, 3 RED. CREW REPORTED ALL 3 MLG FAILED TO RETRACT AS COMMANDED. 3 RED & 3 GREEN MLG INDICATION LIGHTS REMAINED ILLUMINATED THROUGHOUT FLT WITH MLG DOWN. ATTEMPTED RESET USING ALTERNATE MANUAL EXTENSION DOOR, WITH NO HELP. CYCLED MLG HANDLE WITH NO IMPROVEMENT. PERFORMED VISUAL INSP OF ALL 3 MLG & MANUAL GEAR EXTENSION ACCESS DOOR NO DISCREPANCIES NOTED. NO MLG DOWNLOCK PINS INSTALLED. CHKD OMF FOR INBOUND, EXISTING, & PRESENT-LEG FAULTS IAW AMM 46-13-02. NO FAULTS FOUND.PERFORMED PSEU OPS SELF-TEST IAW AMM 32-09-10-740-801. TEST OK. UNABLE TO PERFORM PSEU BITE LRU TEST DUE TO INHIBITED TEST-AIR/GROUND FUNCTION NOT ACTIVE & TAIL/SKID FUNCTION NOT ACTIVE. MESSAGES DISPLAYED. PERFORMED MANUAL EXTENSION SYS ACCESS DOOR SWITCH ADJUST IAW AMM 32-34-00-820-802, PERFORMED SELECTOR/BYPASS VALVE OPS TEST IAW AMM 32-31-51-700-801. OP CHKD SATIS, ALL 3 MLG WORK NORMALLY & ALL 3 LANDING LIGHTS FOUND WORKING NORMAL DURING THE TEST.