Date: 201508
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Aircraft component: Engine Oil Seals
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Distraction; Situational Awareness; Training / Qualification; Confusion
Second reporter function: Technician
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Chart Or Publication; Environment - Non Weather Related; Human Factors; Manuals; Procedure
Primary problem: Human Factors

Narrative: August 2015. In ZZZ; myself Aircraft Maintenance Technician (AMT X) and AMT Y; during a Service Check found a leak from the Integrated Drive Generator (IDG) on the Left-hand Engine. While changing the IDG carbon seal; documents and references were misunderstood. The distractions inside the Hangar aided in misplacement of the O-Ring. The work interruptions from Management distracted us from the task at hand. We preformed the Leak Check and Operational Check and found everything to be within limits. Nothing seemed unusual and we signed off the aircraft. The following day; it was brought to our attention we had placed the O-Ring in the wrong place. While we were discussing this; the aircraft lost oil from the Left Engine and made an emergency landing.I would suggest more descriptive [maintenance] illustrations. A new Warning added to the Maintenance Manual; or internal document added. Availability to faster; more reliable access to manuals. Better training on (IDG) carbon seal replacement.


Second narrative: Aircraft Maintenance Technician (AMT X) and I (AMT Y); were installing a new carbon seal on the IDG on Engine One. During that process; we put a seal in the wrong location. We misinterpreted the diagram depicting where the seal went. Throughout this process we had to keep going back to the [Maintenance] Manual to print out sub-tasks using computers that are exceptionally slow; as well as endure many interruptions/inquiries at the hands of Management which added to our distraction. After installation; we performed the Leak Check in accordance with the Maintenance Manual and there were no leaks so we did not realize our error at the time. During discussion about the project; Supervision found that we had incorrectly installed the O-Ring. By the time we discovered this fact it was the following day; (the mistake happened the day before). As the lines of communication to right this wrong had been opened; the aircraft lost the oil on the Left Engine most likely due to our mistake. The aircraft subsequently performed an emergency landing.  It was easy to misinterpret the diagram in the Maintenance Manual. The interruptions due to slow network access to the online Maintenance Manual and repeated Management interruptions added to the situation.


Synopsis: After their CRJ-200 aircraft had departed; two Aircraft Maintenance Technicians realized they had installed a new carbon seal O-Ring at the wrong location on # 1 Engine Integrated Drive Generator. # 1 Engine lost all oil in flight. Distraction; inadequate and easy to misinterpret maintenance diagrams; work interruptions from Management; lack of training and experience and a slow on-line Maintenance Manual program were noted as contributors.