Maintenance Powerplant; Maintenance Airframe
Situational Awareness; Distraction; Communication Breakdown; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Equipment / Tooling; Procedure
October 2013; late night; I was assigned to perform an engine wash with two other mechanics on an MD-82 aircraft. I prepared the #1 Engine for washing operation and after completion I reconnected the lines and removed the wash ring. The aircraft departed on time the next morning.  On the following day; the aircraft returns to ZZZ and I was assigned to perform an A-Check Inspection with Mechanic Y. I began the inspection with #1 Engine; followed by #2 Engine. After closing the cowling on #2 Engine; I was interrupted for an aircraft move; and a #2 main tire change. I thought that I had completed the #2 Engine Inlet Inspection. I must have missed it. I realize how easy it is to get distracted. From now on I will take the inspection paperwork with me and check the items as I perform them. Interruptions.
I [as Mechanic Y] was assigned the #2 Engine for Engine Wash Card 71-97-05.  I installed the nozzle with the line. Upon finish of the cycles; I serviced the truck with water until full.  When everything was done; I assumed my co-worker; [Mechanic X]; had  disconnected the nozzle when I saw the hose lying down on the ground; so I rolled the hose up. [I was informed] aproximately seven days later; about my mistake; I didn't visually check the engine myself. It's my responsibility to do job right; I forgot to disconnect the nozzle. For some reason I forgot to remove the ring. Whether it was [due to a] change in routine or whatever the cause; I forgot to remove the ring. Lack of communication. I assumed that my co-worker had removed the nozzle ring when I saw the hose lying on the ground. I didn't look in the engine myself.Never assume that another will accomplish the task without checking verbally or physically myself. Also; extend [wash] nozzle line pass engine inlet; to make it more visible from the ground.  Or; possibly [develope] a Tool Checklist as an addition to [Engine Wash Card] paperwork to remove ring and hose in one step at the same time. Complacency. Graveyard Shift.
Two Aircraft Maintenance Technicians (AMTs) were informed that a wash nozzle had not been removed from the inlet of #2 Engine on an MD-82 aircraft; after completing an Engine Wash Card.