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A B737-200 during an FAA ramp check was discovered to have the auxiliary power unit being replaced without circuit breakers being pulled per the maintenance manual.
| Attributes | |
| ACN | 533326 |
| Time | |
| Date | 200112 |
| Day | Wed |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Environment | |
| Light | Dawn |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : maintenance ground : parked |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : airframe technician : powerplant |
| ASRS Report | 533326 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Events | |
| Anomaly | aircraft equipment problem : less severe maintenance problem : improper documentation maintenance problem : improper maintenance non adherence : far non adherence : published procedure |
| Independent Detector | other other : person 3 |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other other |
| Factors | |
| Maintenance | contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : installation |
| Supplementary | |
| Problem Areas | Aircraft Maintenance Human Performance |
| Primary Problem | Maintenance Human Performance |
Narrative:
Aircraft X had APU change due to surging. We had to wait for another aircraft to push out of the hangar. The aircraft did not get into the hangar until XA30 am and had an XO15 flight. The paperwork calls for circuit breakers to be pulled to remove power from APU. We had pulled the APU t-handle, turned the battery switch off, the external power door was closed and the aircraft was grounded. We were the only ones on the aircraft. The removal of all power from the aircraft was perceived to be rendering the aircraft safe for APU removal. I had the perception that removing power from the aircraft was a safe alternate to puling circuit breakers. It was not my intent to work on the aircraft in an unsafe condition. I feel that a better communication process and the knowledge that removing power from the aircraft is not a substitute for pulling circuit breakers will help correct this error in the future.
Original NASA ASRS Text
Title: A B737-200 DURING AN FAA RAMP CHK WAS DISCOVERED TO HAVE THE AUX PWR UNIT BEING REPLACED WITHOUT CIRCUIT BREAKERS BEING PULLED PER THE MAINT MANUAL.
Narrative: ACFT X HAD APU CHANGE DUE TO SURGING. WE HAD TO WAIT FOR ANOTHER ACFT TO PUSH OUT OF THE HANGAR. THE ACFT DID NOT GET INTO THE HANGAR UNTIL XA30 AM AND HAD AN XO15 FLT. THE PAPERWORK CALLS FOR CIRCUIT BREAKERS TO BE PULLED TO REMOVE PWR FROM APU. WE HAD PULLED THE APU T-HANDLE, TURNED THE BATTERY SWITCH OFF, THE EXTERNAL PWR DOOR WAS CLOSED AND THE ACFT WAS GNDED. WE WERE THE ONLY ONES ON THE ACFT. THE REMOVAL OF ALL PWR FROM THE ACFT WAS PERCEIVED TO BE RENDERING THE ACFT SAFE FOR APU REMOVAL. I HAD THE PERCEPTION THAT REMOVING PWR FROM THE ACFT WAS A SAFE ALTERNATE TO PULING CIRCUIT BREAKERS. IT WAS NOT MY INTENT TO WORK ON THE ACFT IN AN UNSAFE CONDITION. I FEEL THAT A BETTER COM PROCESS AND THE KNOWLEDGE THAT REMOVING PWR FROM THE ACFT IS NOT A SUBSTITUTE FOR PULLING CIRCUIT BREAKERS WILL HELP CORRECT THIS ERROR IN THE FUTURE.
Data retrieved from NASA's ASRS site as of July 2007 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.