Maintenance Airframe; Maintenance Powerplant
Situational Awareness; Troubleshooting; Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Flight Crew Inflight Shutdown; Flight Crew Diverted; General Maintenance Action
Human Factors; Procedure
We were called out to aircraft for a #1 hydraulic system quantity low. Serviced the #1 system in accordance with Aircraft Maintenance Manual (AMM). We noticed Skydrol leaking out of the #1 engine drain port. Opened the #1 engine cowl and found the #1 Engine Driven Pump (EDP) to be leaking when the engine was motored over. Proceeded to remove and perform deactivation procedures of the #1 EDP in accordance with AMM. After completion of the deactivation ran the #1 engine for leaks and no leaks were noted. Aircraft was then dispatched with a #1 EDP deferred.Aircraft was dispatched with a #1 EDP [deactivated] and was diverted due to #1 engine loss of engine oil resulting in engine shut down.It would be better if the AMM would be more detailed in the leak check procedure.
A Maintenance Technician reported that following the deferral of an engine driven hydraulic; the aircraft experienced an inflight engine shutdown due to the loss of engine oil.