MD-83
Maintenance Airframe; Maintenance Powerplant
Maintenance Lead Technician 7; Maintenance Technician 15
Confusion; Situational Awareness; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Procedure
The incorrect fuel control part number was installed on a JT8D engine for the bleed valve affectivity of that engine. I miss-identified a bleed control valve as a start bleed control valve which is only installed on pre-service bulletin engines and requires a -12 fuel control unit. The engine being worked on was a post service bulletin engine with no start bleed control valve and required a -15 fuel control unit. I instructed the mechanics to install the -12 FCU and told them that I verified that it was a pre-service bulletin engine. A contributing factor was my lack of understanding of pre and post service bulletin bleed valve components and identification of same components. The issue was discovered a week later during troubleshooting of a slow to spool discrepancy on the same engine. The FCU was replaced with a -15. I should have verified what a start bleed control valve looked like. I thought I knew but had not worked that system before and in the end; an assumption was made about the part as to shape and mounting location; etc. A power plant matrix with engine serial number and service bulletins accomplished as well as bleed configurations would be helpful. Regardless of a matrix or not the responsibility for correct part installation lies with me.
Air carrier maintenance personnel installed the incorrect engine fuel control unit for the affectivity due to confusion over configuration and service bulletin status.