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A B737-300 mechanic describes being informed of an air turnback after gear unsafe indication; the right uplock sensor was not properly secured.
| Attributes | |
| ACN | 774112 |
| Time | |
| Date | 200802 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : powerplant technician : airframe |
| ASRS Report | 774112 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : powerplant technician : airframe |
| ASRS Report | 774119 |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : improper maintenance |
| Independent Detector | other other : 1 |
| Resolutory Action | flight crew : diverted to another airport |
| Consequence | other |
| Factors | |
| Maintenance | contributing factor : work cards performance deficiency : scheduled maintenance performance deficiency : testing performance deficiency : installation |
| Supplementary | |
| Problem Areas | Aircraft Maintenance Human Performance |
| Primary Problem | Maintenance Human Performance |
Narrative:
I was informed that aircraft had an air turn-back earlier in the day due to an unsafe gear indication. It was found that the #3 pin for the right uplock sensor was not locked into place. The pin was reseated and all operations checks were good. I installed the right uplock and wired the sensor during a gear change. All checks on the sensor were good during the gear change and I felt confident that everything was installed correctly. I feel now though that the pin was not properly locked into place and with the vibration and turbulence of takeoff; the pin became unseated resulting in the unsafe gear indication. Supplemental information from acn 774119: I was involved in a gear change on the same aircraft the night before. I was working on the left gear which involved changing the gear doors and actuators.
Original NASA ASRS Text
Title: A B737-300 MECHANIC DESCRIBES BEING INFORMED OF AN AIR TURNBACK AFTER GEAR UNSAFE INDICATION; THE RIGHT UPLOCK SENSOR WAS NOT PROPERLY SECURED.
Narrative: I WAS INFORMED THAT ACFT HAD AN AIR TURN-BACK EARLIER IN THE DAY DUE TO AN UNSAFE GEAR INDICATION. IT WAS FOUND THAT THE #3 PIN FOR THE R UPLOCK SENSOR WAS NOT LOCKED INTO PLACE. THE PIN WAS RESEATED AND ALL OPS CHKS WERE GOOD. I INSTALLED THE R UPLOCK AND WIRED THE SENSOR DURING A GEAR CHANGE. ALL CHKS ON THE SENSOR WERE GOOD DURING THE GEAR CHANGE AND I FELT CONFIDENT THAT EVERYTHING WAS INSTALLED CORRECTLY. I FEEL NOW THOUGH THAT THE PIN WAS NOT PROPERLY LOCKED INTO PLACE AND WITH THE VIBRATION AND TURB OF TKOF; THE PIN BECAME UNSEATED RESULTING IN THE UNSAFE GEAR INDICATION. SUPPLEMENTAL INFO FROM ACN 774119: I WAS INVOLVED IN A GEAR CHANGE ON THE SAME ACFT THE NIGHT BEFORE. I WAS WORKING ON THE L GEAR WHICH INVOLVED CHANGING THE GEAR DOORS AND ACTUATORS.
Data retrieved from NASA's ASRS site as of May 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.