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Two mechanics report about a crew oxygen bottle that was removed; serviced and reinstalled on a B737-700. Same bottle pressure had dropped to 100 psi four days later during crew oxygen mask preflight check.
| Attributes | |
| ACN | 809872 |
| Time | |
| Date | 200810 |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-700 |
| Flight Phase | ground : maintenance |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| ASRS Report | 809872 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| ASRS Report | 809871 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other other : 1 |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other |
| Factors | |
| Maintenance | performance deficiency : testing |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance Maintenance Human Performance |
| Primary Problem | Aircraft |
Narrative:
During the service check; it was found that the crew oxygen bottle required servicing. Crew oxygen bottle was removed from the aircraft and svced to full per amm 12-15-21. Reinstalled the crew oxygen bottle to aircraft and performed all required checks per amm 12-15-21 (cracked the valve all the way open and safety-wired and closed the panel) system operations check was performed by mr XXX. Crew oxygen service completed per amm 12.15.21. Supplemental information from acn 809871: what I had to do is operations check the system per amm 35-12-00 and the system is good. After that check; I don't know what happened. From oct/xa/08 after the service; found crew oxygen pressure drop to 100 psi during mask check on oct/08.
Original NASA ASRS Text
Title: TWO MECHANICS REPORT ABOUT A CREW OXYGEN BOTTLE THAT WAS REMOVED; SERVICED AND REINSTALLED ON A B737-700. SAME BOTTLE PRESSURE HAD DROPPED TO 100 PSI FOUR DAYS LATER DURING CREW OXYGEN MASK PREFLIGHT CHECK.
Narrative: DURING THE SVC CHK; IT WAS FOUND THAT THE CREW OXYGEN BOTTLE REQUIRED SVCING. CREW OXYGEN BOTTLE WAS REMOVED FROM THE ACFT AND SVCED TO FULL PER AMM 12-15-21. REINSTALLED THE CREW OXYGEN BOTTLE TO ACFT AND PERFORMED ALL REQUIRED CHKS PER AMM 12-15-21 (CRACKED THE VALVE ALL THE WAY OPEN AND SAFETY-WIRED AND CLOSED THE PANEL) SYSTEM OPS CHK WAS PERFORMED BY MR XXX. CREW OXYGEN SVC COMPLETED PER AMM 12.15.21. SUPPLEMENTAL INFO FROM ACN 809871: WHAT I HAD TO DO IS OPS CHK THE SYSTEM PER AMM 35-12-00 AND THE SYSTEM IS GOOD. AFTER THAT CHK; I DON'T KNOW WHAT HAPPENED. FROM OCT/XA/08 AFTER THE SVC; FOUND CREW OXYGEN PRESSURE DROP TO 100 PSI DURING MASK CHK ON OCT/08.
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.