What was found
SHIP 3231 DISC: AT GATE, DEPLANING COMPLETE, GROUND POWER WENT OFF LINE WITH THE APU OFF, AIRCRAFT WENT DARK, SMOKE STARTED COMING FROM BEHIND THE FCU. DEBRIEFED FLIGHT CREW. VERIFIED NO PASSENGERS ONBOARD. POWERED A /C WITH GATE POWER. POWER WAS NOT WITHIN ACCEPTABLE PARAMETERS. INSPECTED F/D WIRING, AVEC COMPONENTS, AND EXT POWER RECEPTACLE. NO FINDINGS. AVEC BITE TEST PASS. REF A320 AMM 21-26. R/R AVEC FILTER. AS A PRECAUTION, R/R FCU REF A320 AMM 22-81. AFS TEST PASSED. STILL REQUIRES CAT 3 CAPABILITY TEST PERFORMED CAT 3 CAPABILITY TEST REF A320 AMM 22-97. TESTS GOOD . (LP: 5972308)