Narrative:

Aircraft X had a status message 'hpsov left.' accomplished MEL 36-3 and procedures manual 36-3. 5 days later; it was brought to my attention that the left prsov was locked out. After viewing illustrations of the prsov and hpsov; procedures manual illustrations are vague on location of the valves. Upon arrival at destination; maintenance locked out the correct valve.

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Original NASA ASRS Text

Title: TWO MECHANICS WORKING A B777 STATUS MESSAGE HPSOV-L; ACCOMPLISH AN MEL DEFERRAL; BUT; INADVERTENTLY LOCK OUT THE PRESSURE REGULATING SHUTOFF VALVE (PRSOV); INSTEAD OF THE HPSOV FOR THE LEFT ENGINE.

Narrative: ACFT X HAD A STATUS MESSAGE 'HPSOV L.' ACCOMPLISHED MEL 36-3 AND PROCS MANUAL 36-3. 5 DAYS LATER; IT WAS BROUGHT TO MY ATTN THAT THE L PRSOV WAS LOCKED OUT. AFTER VIEWING ILLUSTRATIONS OF THE PRSOV AND HPSOV; PROCS MANUAL ILLUSTRATIONS ARE VAGUE ON LOCATION OF THE VALVES. UPON ARR AT DEST; MAINT LOCKED OUT THE CORRECT VALVE.

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.