Narrative:

Early morning prior to event, I worked a deferred item already on aircraft of 'left engine electronic engine control C1' status message previously MEL'ed under 73-21-01E. The troubleshooting procedure suggested replacement of the air/oil heat exchanger valve which we did not stock, so I supplemented the original deferral. However, I changed the MEL reference as discussed with our maintenance control representative, to 75-21-02A which required verification that the air/oil heat exchanger valve was open and removal and stowage of the valve connector. I opened up the engine per the MEL and maintenance manual and located the heat exchanger on the left side of engine. Using a mirror, per MEL, I located the valve flappers and verified that they were open and followed the shaft down to what I thought was the air/oil heat exchanger valve and removed the connector and stowed. I actually removed the 2.5 bleed valve actuator connector inadvertently and/or unknowingly. The aircraft had a left engine compressor stall later that morning on takeoff roll, which I believe removing the 2.5 bleed actuator connector was the cause. Subsequent reinstallation of the connector and engine borescope took care of problem and aircraft was returned to service with no further problems. Contributing factors I believe were lack of detail in component location illustrations in manuals, connectors in close proximity not being idented and personal unfamiliarity with PW4060 engine. The maintenance control representative was unfamiliar with the PW4060 also. (We have had initial training, just not much exposure to PW4060.)

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Original NASA ASRS Text

Title: A B767-300 WAS DISPATCHED IN NON COMPLIANCE WITH A DEFERRED ITEM SPECIAL PROC NOT ACCOMPLISHED CORRECTLY RESULTING IN A STALLING L ENG.

Narrative: EARLY MORNING PRIOR TO EVENT, I WORKED A DEFERRED ITEM ALREADY ON ACFT OF 'L ENG ELECTRONIC ENG CTL C1' STATUS MESSAGE PREVIOUSLY MEL'ED UNDER 73-21-01E. THE TROUBLESHOOTING PROC SUGGESTED REPLACEMENT OF THE AIR/OIL HEAT EXCHANGER VALVE WHICH WE DID NOT STOCK, SO I SUPPLEMENTED THE ORIGINAL DEFERRAL. HOWEVER, I CHANGED THE MEL REF AS DISCUSSED WITH OUR MAINT CTL REPRESENTATIVE, TO 75-21-02A WHICH REQUIRED VERIFICATION THAT THE AIR/OIL HEAT EXCHANGER VALVE WAS OPEN AND REMOVAL AND STOWAGE OF THE VALVE CONNECTOR. I OPENED UP THE ENG PER THE MEL AND MAINT MANUAL AND LOCATED THE HEAT EXCHANGER ON THE L SIDE OF ENG. USING A MIRROR, PER MEL, I LOCATED THE VALVE FLAPPERS AND VERIFIED THAT THEY WERE OPEN AND FOLLOWED THE SHAFT DOWN TO WHAT I THOUGHT WAS THE AIR/OIL HEAT EXCHANGER VALVE AND REMOVED THE CONNECTOR AND STOWED. I ACTUALLY REMOVED THE 2.5 BLEED VALVE ACTUATOR CONNECTOR INADVERTENTLY AND/OR UNKNOWINGLY. THE ACFT HAD A L ENG COMPRESSOR STALL LATER THAT MORNING ON TKOF ROLL, WHICH I BELIEVE REMOVING THE 2.5 BLEED ACTUATOR CONNECTOR WAS THE CAUSE. SUBSEQUENT REINSTALLATION OF THE CONNECTOR AND ENG BORESCOPE TOOK CARE OF PROB AND ACFT WAS RETURNED TO SVC WITH NO FURTHER PROBS. CONTRIBUTING FACTORS I BELIEVE WERE LACK OF DETAIL IN COMPONENT LOCATION ILLUSTRATIONS IN MANUALS, CONNECTORS IN CLOSE PROX NOT BEING IDENTED AND PERSONAL UNFAMILIARITY WITH PW4060 ENG. THE MAINT CTL REPRESENTATIVE WAS UNFAMILIAR WITH THE PW4060 ALSO. (WE HAVE HAD INITIAL TRAINING, JUST NOT MUCH EXPOSURE TO PW4060.)

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.