EMB ERJ 170/175 ER/LR
Maintenance Airframe; Maintenance Powerplant
Time Pressure; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Company Policy; Incorrect / Not Installed / Unavailable Part; Logbook Entry; Aircraft; MEL; Procedure; Manuals
This morning; I was told to troubleshoot a BLEED 2 Fault caution message deferral on an ERJ 175. [I] interrogated [the] CMC (Central Maintenance Computer) and found codes that were flagging the high stage bleed valve and the nacelle pressure regulating shutoff valve as two of the major faults. Troubleshot per FIM 36-XX-XX-XXX-XXX but was having difficulty figuring out [the] effectivity of aircraft software version. Found effectivity and troubleshot accordingly. Performed Bleed 2 TM (Technical Manual) Controller IBIT (Initiated Built-In Test) both channels and the check passed. The discrepancy was signed off as a transitory condition per FIM 36-XX-XX and the valve was un-deferred.After paperwork was done; the Supervisor and I revisited the issue and decided it was smart to run the engine to make absolutely sure the issue was resolved. While trying to engage the RH (Right Hand) engine bleed air system; the BLEED 2 Fault caution message came back into view; flagging the NAPRSOV (Nacelle Pressure Regulating Shutoff Valve) - the valve that was supposedly deferred before troubleshooting started. The aircraft was needed for dispatch so I consulted Inspections/Quality Control about fixing paperwork to allow for the valve to remain on deferral instead of clearing the deferral like originally intended. They said they'd try and later told me to create a non-routine write-up for the troubleshooting work performed and [to] carry forward the original deferral due to lack of time; aircraft needed for dispatch. I did said paperwork and re-deferred what I thought was the NAPRSOV referencing MEL 36-XX-XX; with MEL 36-YY-YY accompanying it as a requirement to apply MEL 36-XX-XX; but I didn't notice that it was in fact not the NAPRSOV to begin with but the high stage bleed valve that was deactivated initially. Due to paperwork and system issues; Contract Maintenance was called out to the aircraft at a different base to verify the maintenance action being correctly complied with and found the wrong valve deferred. I was in a rush due to the aircraft being needed for dispatch and flustered with the complexities of troubleshooting this issue. I looked up the deactivation process for the NAPRSOV but accidentally overlooked the fact that it was the aft valve not the forward one like I had thought it was. [Some suggestions could be] possibly labeling the valves somehow; such as a metal placard and band that can be taken off and installed on a new valve in the event that it needs to be changed. A toolbox talk would be nice to spread awareness of the different places of the valves. Due to the part numbers of both the NAPRSOV and the high stage bleed valve being the same; the only difference in function is where they're installed on the aircraft; which happens to be almost right next to each other. Though; that being said; now that I think about it the AMM isn't unclear about it in the first place; so I can't really blame unclear paperwork. ALSO a toolbox talk about where to find epic load and CMC LDI software versions on an ERJ 175 would have helped as well.
Technician reported experiencing confusion and deferred the wrong bleed valve and applied the wrong MEL.