A310 CREW HAD THE LCL MECH DEFER THE WRONG SIGNAL GENERATOR UNIT.
Synopsis
A310 CREW HAD THE LCL MECH DEFER THE WRONG SIGNAL GENERATOR UNIT.
Narrative
DURING THE CAPT'S COCKPIT SET-UP; THE CAPT'S ELECTRONIC FLT INST SYS SIGNAL GENERATOR UNIT FAILED. THE EFIS SYMBOLOGY BECAME BLURRY AND THEN 2 DIAGONAL WHITE LINES APPEARED ON THE PFD AND THE NAV DISPLAY; INDICATING THAT THE INSTS THEMSELVES WERE FUNCTIONING BUT THE SIGNAL GENERATOR UNIT THAT DRAWS THE PICTURES ON THE INSTS WAS FAULTY. ON THE CAPT'S SWITCHING PANEL; HE SELECTED 'SGU ON SYS 3' TO VERIFY SYS 3 OP. AN ENTRY WAS MADE INTO THE ACFT MAINT LOG STATING 'CAPT'S EFIS SIGNAL GENERATOR UNIT INOP. SELECTED TO SYS 3.' ACFT MAINT ARRIVED TO VERIFY THE MALFUNCTION AND BEGIN REPAIR. HERE IS THE FIRST MISTAKE THE CAPT MADE. HE DID NOT STOP HIS COCKPIT PREPARATION AND CONSULT THE MEL TO DETERMINE THE PARTICULARS OF THIS ONE FAILURE. HE CONTINUED ON WITH HIS COCKPIT PREPARATION WHILE THE MAINT TECHNICIANS WERE WORKING. AFTER AN INTERVAL OF TIME; THE MAINT TECH ANNOUNCED THAT THE ITEM HAD BEEN DEFERRED; PRESENTED THE ACFT MAINT LOG TO THE CAPT; AND PLACED AN ORANGE DEFERRED STICKER NEXT TO THE 'SIGNAL GENERATOR UNIT ON SYS 3' SWITCH ON THE CAPT'S SWITCHING PANEL. THE MAINT ACTION WAS RECORDED AS FOLLOWS: 'PLACED ON MEL 31-51-01-02 ECAM SIGNAL GENERATOR UNIT #1 INOP. CAT 'C' EXPIRES SEP/SAT/03. CTL NUMBER X.' HERE IS THE SECOND MISTAKE THE CAPT MADE. HE DID NOT SPECIFICALLY REVIEW THE MAINT SIGNOFF TO ENSURE THAT THE ORIGINAL PROB HAD BEEN FIXED. HE READ THE SIGNOFF; LOOKED AT THE ORANGE STICKER; AND WAS SATISFIED THAT MAINT HAD DONE THEIR JOB. THUS; THE CREW FINISHED THEIR DUTIES; BLOCKED OUT (BY NOW 7 HRS 36 MINS AFTER THE CAPT'S SHOW TIME); AND TOOK OFF. ONLY WHEN PREPARING TO HAVE THEIR FLT RELEASE AMENDED AFTER TKOF FOR THE INOP SIGNAL GENERATOR UNIT DID THE CAPT NOTICE THE ERROR. THE MAINT TECHNICIAN HAD DEFERRED THE WRONG SIGNAL GENERATOR UNIT. THE WRITE-UP SPECIFICALLY STATED THE EFIS SIGNAL GENERATOR UNIT: ELECTRONIC FLT INSTS SYS SIGNAL GENERATOR UNIT. THE TAB FOR SECTION X OF THE ACFT'S MEL SAYS 'FLT INSTS;' SO I MUST ASSUME THAT THIS IS WHERE THE MAINT TECHNICIAN LOOKED FOR HIS GUIDANCE. HOWEVER; THE TABLE OF CONTENTS PAGE OF SECTION X IS LABELED 'INDICATING AND RECORDING.' THERE IS NOT ONE SINGLE FLT INST LISTED IN SECTION X. THEY ARE ALL IN SECTION Y 'NAV.' THE ONLY SIGNAL GENERATOR UNIT LISTED IN SECTION X IS FOR THE ECAM SYS. I BELIEVE THAT THE MAINT TECHNICIAN MADE AN HONEST MISTAKE. HE WAS LOOKING IN THE FLT INSTS SECTION OF THE ACFT MAINT LOG TO DEFER AN INOP SIGNAL GENERATOR UNIT. HE FOUND A SIGNAL GENERATOR UNIT; BUT IT WAS FOR ANOTHER SYS. HE DEFERRED THE ONLY SIGNAL GENERATOR UNIT HE FOUND IN THE FLT INSTS SECTION AND BELIEVED HE HAD ACCOMPLISHED THE CORRECT TASK. THE CAPT RETAINS THE ULTIMATE RESPONSIBILITY HERE; AND HE DID NOT DO HIS JOB. 1) THE CAPT DID NOT CEASE HIS COCKPIT PREPARATION AND CONSULT THE MEL WHEN THIS PROB AROSE. (HE WILL IN THE FUTURE.) HE SHOULD HAVE DETERMINED IF THE ACFT WAS UP OR DOWN WITH THE #1 EFIS SIGNAL GENERATOR UNIT INOP: IT WAS NOT. HE SHOULD HAVE TOLD MAINT THIS WHEN THEY ARRIVED. 2) THE CAPT DID NOT ENSURE THAT THE MAINT PERFORMED MATCHED UP WITH THE PROB THAT HAD BEEN WRITTEN UP. (HE WILL IN THE FUTURE.) 3) THE ACR MEL WAS NO HELP TO THE MAINT TECHNICIAN IN THIS CASE. AS AN ASIDE; ON THE RETURN LEG OF THIS FLT; THE L HALF OF THE CAPT'S NAV DISPLAY FAILED DURING PREFLT. HE STOPPED HIS COCKPIT SETUP; CONSULTED THE MEL; WROTE UP THE DISCREPANCY; AND NOTIFIED MAINT. ONCE THEY WERE FINISHED; HE REVIEWED THEIR SIGNOFF; REVIEWED THE MEL; AMENDED HIS FLT RELEASE; THEN DEPARTED ON THE FLT. OLD DOGS CAN INDEED LEARN NEW TRICKS!
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.