What was found
(CAN) FLIGHT WAS AT FL350 WHEN THE LANDING, EXTENDED WITH OUT COMMAND. THE CAPTAIN HAS DECLARED A PAN PAN AND IS RETURNING. MORE INFO TO FOLLOW WHEN IT BECOMES AVAILABLE. FROM CREW, LEFT MAIN GEAR DOORS OPENED WITHOUT COMMAND AND THEN CLOSED UNCOMMANDED A FEW MINUTES LATER. RETURNING TO DEPARTURE AS A PRECAUTION. CONTINUED FROM STEP 4 OF FMR: PROXIMITY SENSOR 32GA REPLACED IAW AMM 32-31-73-400 AND TESTED OK. STEP 5: LANDING GEAR SAFETY VALVE, 49GA, RELAY 48GA & RELAY 53GA REPLACED. FUNCTIONAL CK C/O IAW AMM TASK 32-31-00-710-005, OK. LT MLG DOOR UPLOCK REPLACED IAW AMM 32-31-33-400-002A AND FMR ITEMS 1 TO 5 ACCOMPLISHED GEAR SWING AND FREEFALL ACCOMPLISHED ON FMR M2042174, NO FAULTS FOUND.