Narrative:

Aircraft X had air turn back due to hpsov status message. At gate I instructed mechanics that we would like to use MEL relief. This required them to lock closed the hpsov and install a shorting cap on plug at hp controller on nbr 1 engine. Mr X retrieved the shorting cap for them and I went to cockpit. A few minutes later mechanics said the lockout pin was missing from valve. I got up on ladder and showed them where the pins are on the valves. I left the engine to deal with a cabin write-up. When I returned the engine was being closed and I was told the hpsov was locked closed and shorting cap installed. I then completed MEL relief. The aircraft left after fueling and approximately 30 minutes later I was told aircraft has another air turn back same problem but with 0 psi from engine. At this time I contacted the mechanics and they showed me the valve that they locked closed in the amm. This valve was the prv which is near the hpsov and same P/north. When aircraft parked and engine opened; the mechanics unlocked the prv and locked closed the hpsov per MEL relief. I determined that the wrong valve was locked out because the engine had pressure before any maintenance had occurred. When the flight crew reported that engine had 0 psi I figured that locking out the prv would do this. Upon contacting the mechanics this was figured out 30 minutes before aircraft landed. The mechanics first unlocked the prv and then locked closed the hpsov. Verified shorting plug correctly installed. Then engine closed and ran engine for check out per maintenance control. Check out was good. Later the mechanics said that I pointed to the prv to lock closed when I showed them where the lockout pin was stowed. This is incorrect. They were told to lock the hpsov and I believe they got confused which valve was the hpsov. Both valves are the same and on the prv the tag says hpsov with the part number of the hpsov. Both valves are next to each other. When hpsov installed in prv position the name plate should be covered and visibility-versa.callback conversation with reporter revealed the following information: reporter stated the close proximity of the hpsov and prv valves on the left side of the pw 4000 engine contributes to the incorrect valve being locked out; even with experienced mechanics. Adding to the problem of determining which of the two valves to close manually for flight; is the data plate on both valves state 'hpsov' and have the same part number. When ordering a prv valve from their company stores; the part numbers listed in the ipc will be different; even though on the valves they have the same number. Reporter stated since this incident his carrier has given all their mechanics; including the contract mechanics who service the same engines; refresher courses on their engine pneumatic systems. Another issue with deferring the hpsov is the shorting cap that is installed on the hpsov controller on the lower side of the engine; doesn't; or hasn't; always been removed when the hpsov is replaced and aircraft released for service. This shorting cap interrupts a valve disagree light from coming on in the cockpit and EICAS messages for the hpsov are also inhibited. His carrier has also submitted changes to their MEL procedures; to include a write-up for the shorting plug; or shorting cap; to be removed when the hpsov is replaced. The prv valve cannot be deferred. Reporter stated he hopes the MEL changes will include some type of specific pictorial location for each valve; or perhaps some identification on the separate electrical harnesses to each valve.

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Original NASA ASRS Text

Title: A MAINT SUPERVISOR DESCRIBES HOW CONTRACT MECHANICS MISTAKENLY LOCKED THE PRV VALVE IN THE CLOSED POSITION INSTEAD OF THE HPSOV; ON THE #1 ENG OF A B767-300; CAUSING A SECOND AIR TURN BACK.

Narrative: ACFT X HAD AIR TURN BACK DUE TO HPSOV STATUS MSG. AT GATE I INSTRUCTED MECHANICS THAT WE WOULD LIKE TO USE MEL RELIEF. THIS REQUIRED THEM TO LOCK CLOSED THE HPSOV AND INSTALL A SHORTING CAP ON PLUG AT HP CONTROLLER ON NBR 1 ENGINE. MR X RETRIEVED THE SHORTING CAP FOR THEM AND I WENT TO COCKPIT. A FEW MINUTES LATER MECHANICS SAID THE LOCKOUT PIN WAS MISSING FROM VALVE. I GOT UP ON LADDER AND SHOWED THEM WHERE THE PINS ARE ON THE VALVES. I LEFT THE ENGINE TO DEAL WITH A CABIN WRITE-UP. WHEN I RETURNED THE ENGINE WAS BEING CLOSED AND I WAS TOLD THE HPSOV WAS LOCKED CLOSED AND SHORTING CAP INSTALLED. I THEN COMPLETED MEL RELIEF. THE AIRCRAFT LEFT AFTER FUELING AND APPROX 30 MINUTES LATER I WAS TOLD AIRCRAFT HAS ANOTHER AIR TURN BACK SAME PROBLEM BUT WITH 0 PSI FROM ENGINE. AT THIS TIME I CONTACTED THE MECHANICS AND THEY SHOWED ME THE VALVE THAT THEY LOCKED CLOSED IN THE AMM. THIS VALVE WAS THE PRV WHICH IS NEAR THE HPSOV AND SAME P/N. WHEN AIRCRAFT PARKED AND ENGINE OPENED; THE MECHANICS UNLOCKED THE PRV AND LOCKED CLOSED THE HPSOV PER MEL RELIEF. I DETERMINED THAT THE WRONG VALVE WAS LOCKED OUT BECAUSE THE ENGINE HAD PRESSURE BEFORE ANY MAINTENANCE HAD OCCURRED. WHEN THE FLIGHT CREW REPORTED THAT ENGINE HAD 0 PSI I FIGURED THAT LOCKING OUT THE PRV WOULD DO THIS. UPON CONTACTING THE MECHANICS THIS WAS FIGURED OUT 30 MINUTES BEFORE AIRCRAFT LANDED. THE MECHANICS FIRST UNLOCKED THE PRV AND THEN LOCKED CLOSED THE HPSOV. VERIFIED SHORTING PLUG CORRECTLY INSTALLED. THEN ENGINE CLOSED AND RAN ENGINE FOR CHECK OUT PER MAINT CTL. CHECK OUT WAS GOOD. LATER THE MECHANICS SAID THAT I POINTED TO THE PRV TO LOCK CLOSED WHEN I SHOWED THEM WHERE THE LOCKOUT PIN WAS STOWED. THIS IS INCORRECT. THEY WERE TOLD TO LOCK THE HPSOV AND I BELIEVE THEY GOT CONFUSED WHICH VALVE WAS THE HPSOV. BOTH VALVES ARE THE SAME AND ON THE PRV THE TAG SAYS HPSOV WITH THE PART NUMBER OF THE HPSOV. BOTH VALVES ARE NEXT TO EACH OTHER. WHEN HPSOV INSTALLED IN PRV POSITION THE NAME PLATE SHOULD BE COVERED AND VIS-VERSA.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE CLOSE PROXIMITY OF THE HPSOV AND PRV VALVES ON THE LEFT SIDE OF THE PW 4000 ENGINE CONTRIBUTES TO THE INCORRECT VALVE BEING LOCKED OUT; EVEN WITH EXPERIENCED MECHANICS. ADDING TO THE PROBLEM OF DETERMINING WHICH OF THE TWO VALVES TO CLOSE MANUALLY FOR FLIGHT; IS THE DATA PLATE ON BOTH VALVES STATE 'HPSOV' AND HAVE THE SAME PART NUMBER. WHEN ORDERING A PRV VALVE FROM THEIR COMPANY STORES; THE PART NUMBERS LISTED IN THE IPC WILL BE DIFFERENT; EVEN THOUGH ON THE VALVES THEY HAVE THE SAME NUMBER. REPORTER STATED SINCE THIS INCIDENT HIS CARRIER HAS GIVEN ALL THEIR MECHANICS; INCLUDING THE CONTRACT MECHANICS WHO SERVICE THE SAME ENGINES; REFRESHER COURSES ON THEIR ENGINE PNEUMATIC SYSTEMS. ANOTHER ISSUE WITH DEFERRING THE HPSOV IS THE SHORTING CAP THAT IS INSTALLED ON THE HPSOV CONTROLLER ON THE LOWER SIDE OF THE ENGINE; DOESN'T; OR HASN'T; ALWAYS BEEN REMOVED WHEN THE HPSOV IS REPLACED AND ACFT RELEASED FOR SERVICE. THIS SHORTING CAP INTERRUPTS A VALVE DISAGREE LIGHT FROM COMING ON IN THE COCKPIT AND EICAS MESSAGES FOR THE HPSOV ARE ALSO INHIBITED. HIS CARRIER HAS ALSO SUBMITTED CHANGES TO THEIR MEL PROCEDURES; TO INCLUDE A WRITE-UP FOR THE SHORTING PLUG; OR SHORTING CAP; TO BE REMOVED WHEN THE HPSOV IS REPLACED. THE PRV VALVE CANNOT BE DEFERRED. REPORTER STATED HE HOPES THE MEL CHANGES WILL INCLUDE SOME TYPE OF SPECIFIC PICTORIAL LOCATION FOR EACH VALVE; OR PERHAPS SOME IDENTIFICATION ON THE SEPARATE ELECTRICAL HARNESSES TO EACH 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.