Narrative:

I came in to work and was told that we had an issue with a left-hand thrust reverser on a crj-900 aircraft. I was told by supervisor X that a screw was twisted off that normally secures a nylon slider insert on the thrust reverser track; and the slider was broken. I was also informed that we had no parts to replace the screw; but that we were going to accomplish a modification based on a service bulletin (sb). The modification was to drill out the screw and put longer bolts and nuts in place of the screw. Most of our aircraft have already had this service bulletin.I was following instructions of my supervisor to the best of my knowledge. I was unaware that we needed to get an engineering order (eo) to accomplish this task legally. There was no failure or issue with the aircraft. The maintenance; and paperwork was reviewed and rii inspected by mr Y. Supervisor X had already gone home for the day. I was informed one morning [approximately fourteen days later]; that there had been an error [found] by night shift supervisor Z.this event occurred because I trusted someone else's word that I was ok to perform the task; and because I do not have extensive knowledge of our general maintenance manual (gmm). Suggest to just be familiar with the gmm. Don't take someone else's word for it.

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Original NASA ASRS Text

Title: A Mechanic reports performing a repair modification; per his Supervisor's instructions; of a damaged left-hand engine thrust reverser slider track on a CRJ-900 aircraft. He was unaware of the need to get an Engineering Order to accomplish the modification legally.

Narrative: I came in to work and was told that we had an issue with a left-hand thrust reverser on a CRJ-900 aircraft. I was told by Supervisor X that a screw was twisted off that normally secures a nylon slider insert on the thrust reverser track; and the slider was broken. I was also informed that we had no parts to replace the screw; but that we were going to accomplish a modification based on a Service Bulletin (SB). The modification was to drill out the screw and put longer bolts and nuts in place of the screw. Most of our aircraft have already had this Service Bulletin.I was following instructions of my Supervisor to the best of my knowledge. I was unaware that we needed to get an Engineering Order (EO) to accomplish this task legally. There was no failure or issue with the aircraft. The maintenance; and paperwork was reviewed and RII inspected by Mr Y. Supervisor X had already gone home for the day. I was informed one morning [approximately fourteen days later]; that there had been an error [found] by night shift Supervisor Z.This event occurred because I trusted someone else's word that I was ok to perform the task; and because I do not have extensive knowledge of our General Maintenance Manual (GMM). Suggest to just be familiar with the GMM. Don't take someone else's word for it.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.