Narrative:

Aircraft arrived at XA20. They had a log item stating that high pressure valve will not stay open at low power settings or on descent. Performed MEL procedures for hpsov 36-11-02. I inadvertently locked out the wrong valve causing an air turnback; while the lead mechanic did the paperwork and signed for completing MEL procedures; we were working together side by side. I locked out the valve we thought we had the right valve. But the mistake was mine.816264 cbk reporter stated he had locked out the pressure regulating valve (prv) instead of the high pressure shutoff valve (hpsov). Further stating both valves look the same and have the same part numbers.

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Original NASA ASRS Text

Title: A MECHANIC REPORTS A B767-300 ARRIVED WITH A LOG ITEM THE HP VALVE WILL NOT STAY OPEN AT LOW POWER SETTINGS OR ON DESCENT. HE PERFORMED THE MEL PROCEDURE; BUT HE INADVERTENTLY LOCKED OUT THE WRONG VALVE ON #2 ENGINE CAUSING AN AIR TURNBACK.

Narrative: ACFT ARRIVED AT XA20. THEY HAD A LOG ITEM STATING THAT HIGH PRESSURE VALVE WILL NOT STAY OPEN AT LOW PWR SETTINGS OR ON DSCNT. PERFORMED MEL PROCS FOR HPSOV 36-11-02. I INADVERTENTLY LOCKED OUT THE WRONG VALVE CAUSING AN AIR TURNBACK; WHILE THE LEAD MECH DID THE PAPERWORK AND SIGNED FOR COMPLETING MEL PROCS; WE WERE WORKING TOGETHER SIDE BY SIDE. I LOCKED OUT THE VALVE WE THOUGHT WE HAD THE RIGHT VALVE. BUT THE MISTAKE WAS MINE.816264 CBK REPORTER STATED HE HAD LOCKED OUT THE PRESSURE REGULATING VALVE (PRV) INSTEAD OF THE HIGH PRESSURE SHUTOFF VALVE (HPSOV). FURTHER STATING BOTH VALVES LOOK THE SAME AND HAVE THE SAME PART NUMBERS.

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.