Narrative:

In sum: I was informed by my supervisor that I made a mistake of inoping the wrong valve, instead of the high pressure bleed valve I inoped the pressure regulating valve on #4 engine of airlines B747-200. Estimated ground time was less than 2 hours turn around. This is what happened in this event. I am an airline mechanic. I and another mechanic were assigned to receive, work and dispatch this aircraft on nov/zz/96. Besides doing preflight checks, ground handling, fueling and servicing we had 4 log write-ups from the aircraft that needed work. One of the write-ups required was to inoperative the #4 engine high stage bleed valve. I finished oiling the engines and went to the cockpit. My lead man was reading the logbook and told me to open the #4 engine left inboard cowling to inoperative the high stage bleed valve. I went down and opened the #4 engine cowling. After I opened the #4 engine I went back to the office and started looking through the maintenance manual because I didn't know where the valve was located on the engine. My lead followed me into the office and asked me what I was doing and I told him I was trying to locate the valve. The lead had already pointed out the location of the valve to the other mechanic. I asked the other mechanic if he knew the valve location. He said yes and held the valve. I repeated to him, are you sure that is the correct valve? He said the lead told him it was the correct valve. After the valve was inoped we closed up the engine. It was in XXX when it was discovered the wrong valve was inoped closed. It was not corrected, but left open to avoid any delay. On final approach to the terminating station the flight crew could not get #4 engine anti-ice. The airplane landed safely at the airport. There was no other discrepancy reported on the engine or airplane.

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Original NASA ASRS Text

Title: A B747-200 WAS DISPATCHED WITH THE #4 ENG PNEUMATIC SYS AND THE ENG ANTI-ICE SYS INOP DUE TO THE WRONG VALVE RENDERED INOP AND DEFERRED.

Narrative: IN SUM: I WAS INFORMED BY MY SUPVR THAT I MADE A MISTAKE OF INOPING THE WRONG VALVE, INSTEAD OF THE HIGH PRESSURE BLEED VALVE I INOPED THE PRESSURE REGULATING VALVE ON #4 ENG OF AIRLINES B747-200. ESTIMATED GND TIME WAS LESS THAN 2 HRS TURN AROUND. THIS IS WHAT HAPPENED IN THIS EVENT. I AM AN AIRLINE MECH. I AND ANOTHER MECH WERE ASSIGNED TO RECEIVE, WORK AND DISPATCH THIS ACFT ON NOV/ZZ/96. BESIDES DOING PREFLT CHKS, GND HANDLING, FUELING AND SVCING WE HAD 4 LOG WRITE-UPS FROM THE ACFT THAT NEEDED WORK. ONE OF THE WRITE-UPS REQUIRED WAS TO INOP THE #4 ENG HIGH STAGE BLEED VALVE. I FINISHED OILING THE ENGS AND WENT TO THE COCKPIT. MY LEAD MAN WAS READING THE LOGBOOK AND TOLD ME TO OPEN THE #4 ENG L INBOARD COWLING TO INOP THE HIGH STAGE BLEED VALVE. I WENT DOWN AND OPENED THE #4 ENG COWLING. AFTER I OPENED THE #4 ENG I WENT BACK TO THE OFFICE AND STARTED LOOKING THROUGH THE MAINT MANUAL BECAUSE I DIDN'T KNOW WHERE THE VALVE WAS LOCATED ON THE ENG. MY LEAD FOLLOWED ME INTO THE OFFICE AND ASKED ME WHAT I WAS DOING AND I TOLD HIM I WAS TRYING TO LOCATE THE VALVE. THE LEAD HAD ALREADY POINTED OUT THE LOCATION OF THE VALVE TO THE OTHER MECH. I ASKED THE OTHER MECH IF HE KNEW THE VALVE LOCATION. HE SAID YES AND HELD THE VALVE. I REPEATED TO HIM, ARE YOU SURE THAT IS THE CORRECT VALVE? HE SAID THE LEAD TOLD HIM IT WAS THE CORRECT VALVE. AFTER THE VALVE WAS INOPED WE CLOSED UP THE ENG. IT WAS IN XXX WHEN IT WAS DISCOVERED THE WRONG VALVE WAS INOPED CLOSED. IT WAS NOT CORRECTED, BUT LEFT OPEN TO AVOID ANY DELAY. ON FINAL APCH TO THE TERMINATING STATION THE FLC COULD NOT GET #4 ENG ANTI-ICE. THE AIRPLANE LANDED SAFELY AT THE ARPT. THERE WAS NO OTHER DISCREPANCY RPTED ON THE ENG OR AIRPLANE.

Data retrieved from NASA's ASRS site as of July 2007 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.