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A B737-800 maintenance signed off #2 engine start valve stuck open. After pushback on #2 engine start; duct pressure remained at zero. Found debris in start valve.
| Attributes | |
| ACN | 652663 |
| Time | |
| Date | 200503 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : pushback ground : maintenance |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| ASRS Report | 652663 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : published procedure non adherence : far |
| Independent Detector | aircraft equipment other aircraft equipment : pneumatic press indicator other flight crewa other flight crewb |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other other other |
| Factors | |
| Maintenance | contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : inspection performance deficiency : fault isolation performance deficiency : repair |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Flight Crew Human Performance Aircraft Chart Or Publication |
| Primary Problem | Maintenance Human Performance |
Narrative:
Maintenance signed off our stuck engine #2 start valve. After pushback; we started engine #2 and I observed zero duct pressure; indicating the valve was open. After we returned to the gate; maintenance personnel showed me several jagged potato chip sized pieces of metal that jammed the valve open. I suggest adding the following to the MEL; 'after affected engine start; check engine bleeds open; check APU bleed valve and xfeed valve closed; observe duct pressure above zero.' callback conversation with reporter revealed the following information: maintenance had worked on the starter prior to pushback and signed the report off in the maintenance log. When starting the right engine; the duct pressure dropped to indicate the valve had opened but there was no engine rotation. On return to the gate; maintenance opened the cowling and removed the valve finding metal debris holding the valve open. The airplane was removed from service.
Original NASA ASRS Text
Title: A B737-800 MAINT SIGNED OFF #2 ENG START VALVE STUCK OPEN. AFTER PUSHBACK ON #2 ENG START; DUCT PRESSURE REMAINED AT ZERO. FOUND DEBRIS IN START VALVE.
Narrative: MAINT SIGNED OFF OUR STUCK ENG #2 START VALVE. AFTER PUSHBACK; WE STARTED ENG #2 AND I OBSERVED ZERO DUCT PRESSURE; INDICATING THE VALVE WAS OPEN. AFTER WE RETURNED TO THE GATE; MAINT PERSONNEL SHOWED ME SEVERAL JAGGED POTATO CHIP SIZED PIECES OF METAL THAT JAMMED THE VALVE OPEN. I SUGGEST ADDING THE FOLLOWING TO THE MEL; 'AFTER AFFECTED ENG START; CHK ENG BLEEDS OPEN; CHK APU BLEED VALVE AND XFEED VALVE CLOSED; OBSERVE DUCT PRESSURE ABOVE ZERO.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: MAINT HAD WORKED ON THE STARTER PRIOR TO PUSHBACK AND SIGNED THE RPT OFF IN THE MAINT LOG. WHEN STARTING THE R ENG; THE DUCT PRESSURE DROPPED TO INDICATE THE VALVE HAD OPENED BUT THERE WAS NO ENG ROTATION. ON RETURN TO THE GATE; MAINT OPENED THE COWLING AND REMOVED THE VALVE FINDING METAL DEBRIS HOLDING THE VALVE OPEN. THE AIRPLANE WAS REMOVED FROM SVC.
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.