What was found
PDIS 729 32-10 4468 03MAY19 PHX FACT U LOGPAGES:1089760 ON DEPARTURE FROM KPHX, DURING GEAR RETRACTION THE LEFT MAIN GEAR DOOR SHOWED UNLK FOLLOWED FCAM AND QRH. LOWERED THE GEAR NORMALLY AND RETURNE TO PHX. GEAR DOOR UNLK INDICATION APPEARED WITH BOTH SYS 1 AND SYS 2. SHGN 03MAY19 03:44 PHX U PSCU SHOWS CODES 27 & 28 SENSOR NEAR. FACT 03MAY19 13:07 PHX U REMOVED AND REPLACED PROXIMITY DETECTOR PROCESSING UNIT PER MM 32-31-71-04. OPS CHECKS NORMAL. A/C OK FOR SERVICE. SDR INFORMATION: PART NAME: POSITION DETECTION UNIT MANUFACTURER: P/N: BDM 300-3 S/N: 41.