Date: 201902
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Light Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Training / Qualification
Anomaly: Aircraft Equipment Problem Critical; Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: I was assigned maintenance of Aircraft X. The [Deferral Log] sheet listed an MEL (Minimum Equipment List) item stating 'FO (First Officer) seat adjustment' as a fault. Per the [Maintenance Manual] I checked the operation of the seat height adjustment and found that it was in working order. I inspected the harness; in particular the areas of potential pinching/binding due to the seat being lowered onto the harness or it being caught in the seat track. I found a small indentation that appeared to be from the seat being lowered onto the harness. This commonly causes the seat to not operate up. The seat's CB (Circuit Breaker) had been pulled for the MEL and the crew had since manually adjusted the seat to suit their needs.As the seat was now operating; it seemed to me that the harness had been pinched; placed on MEL; then later adjusted off of the harness; relieving the pressure that had caused it to stop functioning. I operated the seat's electrical adjustment fully up and down and followed the [Maintenance Manual]'s flow chart for verifying full operation of the crew seat. Finding the seat adjustment system in fully working order I signed the MEL off as repaired; meaning it to be a general statement of work accomplished rather than that I had performed any actual electrical repair on the harness itself. I could have worded the sign off in a way to more accurately state the work I accomplished; but didn't realize that it would be an issue. I did not researched if the harness itself could be repaired as it didn't seem necessary to accomplish the task. I later was informed that there were reports of smoke and sparks associated with the MEL. I was unaware of this and if I had known; I certainly would have investigated why the CB hadn't popped and where the smoke and sparks had come from. In retrospect I should have referred to the original logbook page; whereby I would have noted the more relevant issue of smoke and sparks that was omitted from the [Deferral Log] page. The MEL and the fix seemed straightforward enough that I did not think to look in the logbook for additional information in order to solve the problem.Further I deemed the harness that I had requisitioned to not be needed for Aircraft X. Another Mechanic needed the same harness for his aircraft. I knew that I had taken the last harness in stock; so I gave it to the other Mechanic. The part wasn't serialized; so I didn't think it would be a problem. I know now that it was a lapse of judgment and won't happen again. I incorrectly entered into the log book that I had repaired the crew seat harness; when I had meant that I had resolved the issue. I did not electrically repair the crew seat harness. Also; as stated above; I was unaware of the report of smoke or sparks by the crew. I would have addressed this issue; had I known. I have learned to be more precise in how I word the work accomplished in the aircraft log book. I have also learned that it is important not just go by what is written on the [Deferral Log] sheet; but to check the actual log book entry for further relevant information.




Synopsis: Maintenance Technician reported accomplishing the troubleshooting on flight crew seat and signed off Minimum Equipment List Item. The Technician later found out that the MEL item also reported smoke and sparks associated with the discrepancy.