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B777-200 was dispatched with 2 deferred items on the left engine bleed valves locked closed. Special MEL procedures for testing valves conflict.
| Attributes | |
| ACN | 709328 |
| Time | |
| Date | 200609 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B777-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : maintenance ground : takeoff roll |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| ASRS Report | 709328 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 150 flight time total : 11700 flight time type : 1000 |
| ASRS Report | 709585 |
| Events | |
| Anomaly | aircraft equipment problem : less severe maintenance problem : improper documentation maintenance problem : improper maintenance maintenance problem : non compliance with mel non adherence : published procedure non adherence : far |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other other |
| Factors | |
| Maintenance | contributing factor : schedule pressure performance deficiency : repair performance deficiency : testing |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Chart Or Publication Aircraft |
| Primary Problem | Maintenance Human Performance |
Narrative:
We had 2 MEL deferrals on the airplane: left engine bleed high pressure shutoff valve (hpsov) and left engine pressure regulating and shutoff valve (prsov) inoperative and deactivated in the 'closed' position. Under the first MEL; the release document flight crew step has us perform the flight manual additional procedure for hpsov locked closed; which has us advance power above 55% N1 and cycle the engine bleed off and on. This conflicts with the second MEL flight crew step which says: 'position associated engine bleed air switch to 'off' for all phases of flight.' these deferrals were 2 days apart. It seems that the prsov procedure should supersede and clear the hpsov procedure.
Original NASA ASRS Text
Title: B777-200 WAS DISPATCHED WITH 2 DEFERRED ITEMS ON THE L ENG BLEED VALVES LOCKED CLOSED. SPECIAL MEL PROCS FOR TESTING VALVES CONFLICT.
Narrative: WE HAD 2 MEL DEFERRALS ON THE AIRPLANE: L ENG BLEED HIGH PRESSURE SHUTOFF VALVE (HPSOV) AND L ENG PRESSURE REGULATING AND SHUTOFF VALVE (PRSOV) INOP AND DEACTIVATED IN THE 'CLOSED' POS. UNDER THE FIRST MEL; THE RELEASE DOCUMENT FLT CREW STEP HAS US PERFORM THE FLT MANUAL ADDITIONAL PROC FOR HPSOV LOCKED CLOSED; WHICH HAS US ADVANCE PWR ABOVE 55% N1 AND CYCLE THE ENG BLEED OFF AND ON. THIS CONFLICTS WITH THE SECOND MEL FLT CREW STEP WHICH SAYS: 'POS ASSOCIATED ENG BLEED AIR SWITCH TO 'OFF' FOR ALL PHASES OF FLT.' THESE DEFERRALS WERE 2 DAYS APART. IT SEEMS THAT THE PRSOV PROC SHOULD SUPERSEDE AND CLR THE HPSOV PROC.
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.