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A mechanic reported that he failed to uncollar and reset a landing gear handle circuit breaker (C/B) after changing the nose gear sequence valve on a B757-200. The C/B was on an MEL for a nose gear 'slow to extend' deferral. The use of a permanent C/B collar instead of the normal temporary C/B collar added to the confusion.
| Attributes | |
| ACN | 871517 |
| Time | |
| Date | 201001 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Component | |
| Aircraft Component | Nose Gear |
| Person 1 | |
| Function | Technician |
| Qualification | Maintenance Airframe Maintenance Powerplant |
| Experience | Maintenance Technician 25 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Deviation - Procedural MEL |
Narrative:
Aircraft was in hangar bay with a nose gear would not extend fault. The nose of the aircraft was jacked and it needed a valve change. Afternoon shift stated that the air data computer vmo/mmo switch had been returned to 'normal' position. We changed the [sequence] valve and noticed the circuit breaker was collared but it had a permanent style collar. We were going to investigate whether it was supposed to be in; or not after the gear swing. We accomplished ten successful nose gear swings and forgot to check on the circuit breaker. I was under the assumption that afternoon shift had reactivated the whole system. When the gear worked I did not even think to check the circuit breaker or the MEL procedure. Possible future fix to avoid in future may be to only use temporary circuit breaker collars.
Original NASA ASRS Text
Title: A Mechanic reported that he failed to uncollar and reset a Landing Gear handle Circuit Breaker (C/B) after changing the Nose Gear Sequence Valve on a B757-200. The C/B was on an MEL for a Nose Gear 'slow to extend' deferral. The use of a Permanent C/B collar instead of the normal Temporary C/B collar added to the confusion.
Narrative: Aircraft was in Hangar bay with a nose gear would not extend fault. The nose of the aircraft was jacked and it needed a valve change. Afternoon shift stated that the ADC VMO/MMO switch had been returned to 'Normal' position. We changed the [Sequence] Valve and noticed the circuit breaker was collared but it had a permanent style collar. We were going to investigate whether it was supposed to be in; or not after the gear swing. We accomplished ten successful nose gear swings and forgot to check on the circuit breaker. I was under the assumption that afternoon shift had reactivated the whole system. When the gear worked I did not even think to check the circuit breaker or the MEL procedure. Possible future fix to avoid in future may be to only use temporary circuit breaker collars.
Data retrieved from NASA's ASRS site as of April 2012 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.