What was found
LAS/RNO - FLT 523 - AIR TURNBACK. RT MAIN GEAR DOOR WOULD NOT INDICATE CLOSED UPON GEAR RETRACTION. AIRCRAFT RETURNED TO LAS WITH NR 2 MAIN GEAR DOOR INDICATING UNLOCKED. AIRCRAFT LANDED WITHOUT INCIDENT. MX PERFORMED RIG CHECK ON UNLOCK AND GROUND OPENING SYSTEM, AND CLEANED UPLOCK MECHANISM AND SENSORS. PERFORMED FUNCTIONAL TEST OF LANDING GEAR DOOR CLOSED DETECTORS PER SIL 32 067. RIG CHECK PERFORMED PER AMM 32 31 33 AND AMM 32 12 00, OPS CHECK NORMAL. AIRCRAFT RETURNED TO SERVICE. (X)