B737-700 MECHANICS REPORT OF MIS-IDENTIFYING AND LOCKING OUT THE PRSOV VALVE ON A #2 ENGINE INSTEAD OF THE HIGH STAGE VALVE.

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ON NOV 07 ACFT XXX ARRIVED FROM XXX 'FLT NUMBER XXX' WITH #2 ENG COWL ANTI-ICE VALVE INOP. LOG PAGE NUMBER XXX. THE VALVE WAS PLACED ON MEL 30-03. PER MEL THE VALVE WAS LOCKED IN THE OPEN POS AND THE HIGH STAGE VALVE IN THE LOCKED CLOSED POS PER MEL 30-03 AND 36-08. WE ALSO USED AMM 36-11 FIGURE 401 TO LOCATE THE HIGH STAGE VALVE. I DISCOVERED LATER THAT I HAD (MISTAKENLY) WROTE THAT WE HAD LOCKED OUT THE HIGH STAGE VALVE IN THE OPEN POS INSTEAD OF THE CORRECT CLOSED POS. I DID CORRECT IT IN (COMPUTER SYS) ON LOG PAGE XXX. THIS MAY HAVE OCCURRED DUE TO 2 REASONS: 1) WE LOCKED THE HIGH STAGE FIRST AND THE ANTI-ICE WE LOCKED OPEN LAST. 2) OPS HAD THE GATE AGENT COME DOWN THE JETWAY AND DISTRACT ME FROM FILLING OUT THE PAPERWORK TO ASK US ABOUT THE MAINT WORK. OPS SHOULD NOT INTERRUPT US AND SHOULD HAVE USED THE ESTABLISHED TECH OPS COM PROCS THROUGH STATION MAINT CTL TO AVOID DISTRACTING US. ACFT XXX DEPARTED XXX TO XXX ON FLT NUMBER XXX. NOW I HAVE LEARNED THAT IT RETURNED THAT DAY TO XXX FROM XXX. THEN CONTINUED TO XXX ON FLT NUMBER XXX BUT MADE A DIVERSION INTO XXX DUE TO NO BLEED AIR FROM #2 ENG. XXX FOUND THAT THE #2 ENG PRSOV VALVE WAS LOCKED CLOSED AND THE HIGH STAGE WAS NOT LOCKED. WE ALL THOUGHT THAT WE HAD LOCKED THE HIGH STAGE CLOSED BUT WE MUST HAVE MISTAKENLY LOCKED OUT THE PRSOV VALVE. WE HAD USED THE AMM 36-11 FIGURE 401 TO HELP 'IDENT' THE VALVE LOCATION. IT ISN'T TOO CLR AND CAN BE CONFUSING IF YOU DON'T DEAL WITH IT ROUTINELY. IT WOULD HELP TO HAVE THE HIGH STAGE VALVE SHOWN ON THE MEL PAGES. WE ALL THOUGHT IT WAS THE HIGH STAGE VALVE. IT IS EASY TO MISIDENT. ALSO; WE WERE AWARE THAT THE DEP TIME WAS GETTING CLOSE. I ALSO WAS WORKING 2 DIFFERENT GATES. THIS KEPT ME BUSY; GOING TO EACH GATE ONE AFTER ANOTHER WITHOUT HARDLY A MOMENTS BTWN. I HOPE THIS RPT HELPS PREVENT ANY SIMILAR MISTAKES IN THE FUTURE. AS ABOVE I CORRECTED LOG PAGE XXX. STATING THAT THE PAGE SHOULD STATE LOCKED IN OPEN POS WAS IN ERROR AND THAT IT SHOULD STATE LOCKED IN CLOSED POS. THE ANTI-ICE VALVE HAS BEEN REPLACED ON GRAVEYARD SHIFT AND HIGH STAGE RETURNED TO NORMAL. XXX CORRECTED THE PRSOV BY UNLOCKING IT AND LOCKING THE HIGH STAGE WHEN THE ACFT DIVERTED TO XXX SO I WAS TOLD. AMM 36-11 FIGURE 401 VALVE NOT CLRLY IDENTED; MEL 30-03 AND 36-11 DOESN'T IDENT VALVES IN MEL DISPATCH PROCS. OPS DISTR AND INTERRUPTIONS WHILE DOING PAPERWORK AND MAINT TASK. OPS NOT USING ESTABLISH STATION COMS WORKING 2 GATES CONTRIBUTES TO FATIGUE AND LITTLE TIME TO THOROUGHLY REVIEW TASK. PRESSED TO MAKE ON-TIME DEP. SUPPLEMENTAL INFO FROM ACN 762556: I WAS TOLD AN INCIDENT HAD OCCURRED WITH ACFT XXX CONCERNING MEL DISPATCH PROC OF PNEUMATIC HIGH STAGE VALVE. THE FOLLOWING ACTION TOOK PLACE. THE PREVIOUS DAY I WAS TOLD BY MY LEAD TECHNICIAN TO HELP XXX TO OPEN THE ENG #2 COWL TO LOCK THE HIGH STAGE VALVE IN THE CLOSED POS PER MEL 36-08. AFTER LOOKING AT MM 36-11 AND SCHEMATIC; XXX AND I AGREED THE VALVE WE WERE ABOUT TO LOCK IN CLOSED POS WAS THE HIGH STAGE VALVE. WE PROCEEDED WITH THE TASK IN WHICH WE HAD DIFFICULTY PUSHING THE LOCKING TAB IN. WITH THE ASSISTANCE OF THE LEAD WE FINALLY ACCOMPLISHED THE JOB. I ALSO HELPED XXX TO LOCK THE ANTI-ICE VALVE IN OPEN POS ON THE SAME ENG. WE CLOSED THE COWLING AND I STARTED SVCING THE ENGS WITH OIL WHILE XXX TOOK CARE OF THE PAPERWORK. I HAD SEVERAL ACFT WORKING AT THE SAME TIME WE WERE LOCKING OUT THE VALVE. SLOWING THE PACE AND ALLOWING OTHER ACFT TO WAIT WOULD HAVE BEEN A WISE CHOICE DEVOTING ALL OF MY ATTN TO THE MEL DISPATCH PROC OF ACFT XXX ENG. IN ADDITION; I HAVE REVIEWED THE AMM 36-11-06 000 TO CLR UP THE CONFUSING IMAGES OF THE 2 VALVES. SUPPLEMENTAL INFO FROM ACN 761653: AT APPROX XA45 I WENT TO CHK ON PROGRESS OF 2 TECHS WORKING ACFT XXX #2 ENG. TECHS HAD AMM AND MEL ON HAND TO PLACE #2 ENG ANTI-ICE VALVE ON MEL. TECH #1 WAS HAVING DIFFICULTY ENGAGING LOCK TO LOCK IN CLOSED POS; I ASSISTED TO PUSH IN LOCK AND TIGHTENED THE LOCK SCREW. TECH #1 WAS STANDING NEXT TO ME AS THIS WAS DONE; HE WAS SATISFIED WITH THERESULT; I LEFT THE ACFT AND RETURN TO THE ZONE. I RETURNED AGAIN TO CHK ON THE PROGRESS. TECH #1 WAS IN THE PROCESS OF LOCKING THE A/I VALVE IN THE OPEN POS; I DID VERIFY THE VALVE WAS LOCKED OPEN. I RETURNED TO THE ZONE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THERE WERE PREVIOUS AND SUBSEQUENT MIS-IDENTIFYING OF THE PRESSURE REGULATING SHUTOFF VALVE (PRSOV) WITH THE HIGH STAGE VALVE. ALL OF THE INCIDENTS INVOLVED NOSE COWL ANTI-ICE VALVE WRITE-UPS WHICH REQUIRED THE ANTI-ICE VALVE TO BE LOCKED OPEN AND THE HIGH STAGE VALVE TO BE LOCKED CLOSED FOR MEL DISPATCH. REPORTER ALSO STATED THEY (MECHANICS) DECIDED TO TAKE THEIR OWN PICTURES OF A CFM-56 ENGINE AND THE DIFFERENT VALVE LOCATIONS ASSOCIATED WITH THE MEL DISPATCH PROCEDURE. HIS COMPANY'S ENGINEERING LIKED WHAT THE MAINT TECHS HAD PUT TOGETHER AND HAS INCORPORATED THESE IMPROVED VALVE LOCATION AND NOMENCLATURE IMAGES IN THEIR MEL PROCEDURES.