Date: 201908
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Powerplant; Maintenance Airframe
Human factors: Training / Qualification; Confusion
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
Result: General Maintenance Action
Contributing factors: Manuals; Procedure; Human Factors
Primary problem: Procedure

Narrative: I was assigned to work Aircraft X for an engine EEC (Electronic Engine Controller) due to 0 day MEL (Minimum Equipment List). When I took over; the EEC was removed and sitting on a table next to the engine. A replacement was ordered on AOG (Aircraft On Ground) previously. When I received the part I realized it was a post-mod EEC; meaning it has only two ports for sense lines. The engine was in pre-mod configuration and still had three sense lines because our EEC was pre-mod meaning three ports. I checked the IPC (Illustrated Parts Catalog) and both EEC's are applicable to the aircraft depending on engine mod status. I checked and we had no pre-mod EEC in the system due to all getting reworked to eliminate the need for moisture removal cards. At this point I called [Maintenance Control] to discuss options. I do not recall who I spoke to but was on the phone for a while as he researched and talked to different desks; engine; engineering and so on. They were not able to give me any info or guidance on the issue. I was in the IPC and had the SB (Service Bulletin) numbers needed to modify the engine to a two line configuration. I spoke with [Maintenance Control] about this and decided to use the reference to get the job done so I printed off a copy. The applicability of the SB was for all engines of that type; which we had. I removed and capped the sense line per the SB; installed the EEC ops checked it good and closed the engine. I then called [Maintenance Control] to report accomplishment of the SB and clear the MEL. At that point he told me they had found an [Engineering Order] and my engine serial number was not on it. He told me we cannot use SB have to use an [Engineering Order]. I then asked for a revision or an EA (Engineering Authorization) to accompany the work. After being on hold for a while he told me that engineering would not issue an EA for that plane. At that point I undid all my work. I reinstalled the sense line and hardware to original configuration; removed the EEC and documented all work in the logbook. At the time I had no reason to believe I could not use the SB as it was applicable. Later I learned that it was special lease and all parts have to remain with the engine and that is why it was not included on the [Engineering Order]. Also later I learned that when a day shift engineer came on shift they then issued an EA allowing them to just cap the line at the box and not remove the line. I did try to get an EA and get the job done as it was the only option. Ultimately the plane never flew and was in the same position as I got it when I turned it over to the next shift.A lack of knowledge and experience with this task was a factor. I was later informed by our compliance department about the section of the [Procedures Manual] that allows use of a SB only if accompanied by an EA. I did try to get one but was not able. The other issue was the fact that it was a special lease and I returned the old EEC to our parts system and not the lease system so it became a bigger issue. I was not aware of that process as I have no way of knowing it is a lease. The updates and info I have available do not show this. Even the [Maintenance Control] agent was unaware of that. I do wonder how many other parts have been changed on that engine that were not routed correctly. This was brought to my attention as there was a concern I was doing work without authorization but I did have a reference. Lack of knowledge on my part was a factor as I should have been aware of the requirements per our [Procedures Manual]. I used a reference material I had available but not the appropriate [Engineering Order].I need to be more aware and take more time researching reference materials to ensure I am following our procedures and always be IAW (In Accordance With). Possibly a better system of cross referencing a SB found in the manuals to our [Engineering Order] system. A placard or stencil of some kind to help front line guys to identify a leased engine. I would have changed other non-MEL items and never known I did not route them correctly.




Synopsis: Maintenance Technician reported they installed unauthorized part while working on an engine.