MD-90 Series (DC-9-90) Undifferentiated or Other Model
Maintenance Airframe; Maintenance Powerplant
Maintenance Inspector 18; Maintenance Technician 16
Training / Qualification; Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Chart Or Publication; Procedure; Manuals; Incorrect / Not Installed / Unavailable Part; Human Factors
I was notified by my Supervisor that two parts that I assigned to a MD-90; Assembly Part Number (P/N) XXXX-1; were effective only on a MD-88 aircraft. At the time of the incident; I was presented with Shop Order YYYY that was created by a Shop Lead Mechanic to give an 'OK to Install' [approval] the axle into the piston. To the best of my knowledge; Maintenance provided me with the Component Maintenance Manual (CMM) paperwork showing me the path in to make the Next Higher Assembly (NHA) part number. The Shop Order YYYY; referenced the MD-90 as CMM 32-21-13 and I can now see that I was most likely using Part Number and 'Effectivity' codes in the MD-88 CMM 32-21-1 Manual. I failed to verify the information that was provided to me from Maintenance actually came from the MD-90 CMM Manual. The potential non-conformance has been corrected.    I feel that the McDonald Douglas CMM Manual could be confusing to the Aircraft Maintenance Technician (AMT) and Inspection; as using the 'Effectivity' usage codes can be used to build-up to the Final Assembly Number given in the Aircraft Illustrated Parts Catalog (IPC) Manual if you misinterpret the [CMM] Manual number. I feel the Landing Gear Inspectors would feel more confident in performing these non-routine processes if we had training on the procedures for this action. At the time of the incident; Landing Gear Inspection did not have a Standard Operating Procedure (SOP) written to address exactly what was expected of them while performing this process. I also feel that making changes to the Shop Order [form] to incorporate an entry to be made by the Inspector; to show the CMM Manual reference to include page and item number would be helpful. This would drive quality to verify the information is correct and accurate for the parts we are assigning to the build and making serviceable.
The [Nose Landing Gear (NLG)] piston and axle were given to me to assign the axle for assembly of Piston/Axle Assembly for MD-90 NLG.  After mechanics installed axle into piston part [of NLG] the [Piston/Axle Assembly] was given back to me to return to service.  The Douglas Component Maintenance Manual (CMM) Manuals are very vague.
Two Landing Gear Inspectors report a MD-90 Nose Landing Gear (NLG) Assembly was inadvertently assembled using MD-88 components. Lack of training; confusion with the Component Maintenance Manual (CMM) including the usage of Part Numbers (P/N) and 'Effectivity' codes that allow build-up to the Next Higher Assembly (NHA) were noted as contributors.