What was found
AFTER TAKEOFF MSGS LT MLG GEAR DISAGREE GEAR DOORS EICAS CPT REPORTED THAT THE NOSE AND R/MLG SHOWED UP AND LOCK. THE LEFT DID NOT SHOW UP AND LOCK. AC TAXI IN WITH LEFT MLG DOOR DOWN ONLY, RED UNSAFE LT ILLUMINATED. INITIAL INSPECTION FOUND THE LDG GR DOOR CLOSE C/B ON THE P34 TRIPPED EVERY TIME AND MLG DOORS WOULD NOT CLOSE. TROUBLESHOT PER WDM 32-35-11 AND FOUND THE LEFT MLG DOOR SAFETY VALVE AT FAULT. R&R LT MLG DOOR SAFETY VALVE PER AMM 32-35-10, OPS AND PANEL OPEN. CLOSED C/B AND JACKED A/C TO PERFORM GEAR SWING. C/B ROTABLE PARTS CHANGE WAS INDICATED - TT 1365204 SN OFF 0039 VALVE, MLG, SAF OFF 64-3235-9-9002 0039 ON 64-3235-9-9002 0049 LEAK CK GOOD. PERFORMED MULTIPLE GEAR SWINGS, ALL CKS GOOD.