|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : zzz.airport|
|Operator||common carrier : air carrier|
|Make Model Name||B737-700|
|Operating Under FAR Part||Part 121|
|Flight Phase||ground : maintenance|
|Affiliation||company : air carrier|
|Function||maintenance : technician|
|Affiliation||company : air carrier|
|Function||maintenance : lead technician|
oversight : supervisor
|Anomaly||aircraft equipment problem : critical|
maintenance problem : improper documentation
non adherence : published procedure
non adherence : far
|Independent Detector||other flight crewb|
|Resolutory Action||none taken : detected after the fact|
|Maintenance||contributing factor : schedule pressure|
performance deficiency : testing
performance deficiency : logbook entry
performance deficiency : non compliance with legal requirements
Chart Or Publication
Maintenance Human Performance
|Primary Problem||Maintenance Human Performance|
Crew called saying they could not align IRS's (adiru's). Was found that night before terminating crew had left adiru's turned on. Then external power was removed from aircraft. Performed maintenance manual procedure to align adiru's in addition to several attempts made by crew; also by powering down aircraft partially; then completely with circuit breakers and total power shutdown. At this time was able to perform normal alignment of navigation system and checked out through HUD that there were no faults. The mistake was that the system was not downgraded or recertified after reinstalling the adiru's and realigning. All system were clear and operating normally at departure. At the time of this incident; I am temping as line mechanic for a 90-day bid to evaluate maintenance requirements for this station. Being a HUD designee; I should have been aware of the recertification requirement; but due to the aircraft delay incurred just was trying to move the aircraft and this fix was fairly nonstandard even though it succeeded in bringing the aircraft back to service status. I should have recertified it with paperwork as I did actually do the chkout to confirm quality of adiru's and navigation system.
Original NASA ASRS Text
Title: A B737-700 THAT COULD NOT ALIGN THE INERTIAL REF UNITS WAS REPAIRED AND DISPATCHED BY A TECHNICIAN NOT CERTIFIED TO SIGN OFF AUTOLAND AND HEADS UP DISPLAY SYS.
Narrative: CREW CALLED SAYING THEY COULD NOT ALIGN IRS'S (ADIRU'S). WAS FOUND THAT NIGHT BEFORE TERMINATING CREW HAD LEFT ADIRU'S TURNED ON. THEN EXTERNAL PWR WAS REMOVED FROM ACFT. PERFORMED MAINT MANUAL PROC TO ALIGN ADIRU'S IN ADDITION TO SEVERAL ATTEMPTS MADE BY CREW; ALSO BY POWERING DOWN ACFT PARTIALLY; THEN COMPLETELY WITH CIRCUIT BREAKERS AND TOTAL PWR SHUTDOWN. AT THIS TIME WAS ABLE TO PERFORM NORMAL ALIGNMENT OF NAV SYS AND CHKED OUT THROUGH HUD THAT THERE WERE NO FAULTS. THE MISTAKE WAS THAT THE SYS WAS NOT DOWNGRADED OR RECERTIFIED AFTER REINSTALLING THE ADIRU'S AND REALIGNING. ALL SYS WERE CLR AND OPERATING NORMALLY AT DEP. AT THE TIME OF THIS INCIDENT; I AM TEMPING AS LINE MECH FOR A 90-DAY BID TO EVALUATE MAINT REQUIREMENTS FOR THIS STATION. BEING A HUD DESIGNEE; I SHOULD HAVE BEEN AWARE OF THE RECERTIFICATION REQUIREMENT; BUT DUE TO THE ACFT DELAY INCURRED JUST WAS TRYING TO MOVE THE ACFT AND THIS FIX WAS FAIRLY NONSTANDARD EVEN THOUGH IT SUCCEEDED IN BRINGING THE ACFT BACK TO SVC STATUS. I SHOULD HAVE RECERTIFIED IT WITH PAPERWORK AS I DID ACTUALLY DO THE CHKOUT TO CONFIRM QUALITY OF ADIRU'S AND NAV SYS.
Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.