Narrative:

I came in and a crj-900; aircraft X; was aircraft on ground (aog) [status] for parts; for a right-hand main landing gear (rh medium large transport) strut repack. We; mechanics Y and Z and myself (mechanic X); received the parts into the hangar. Mechanics Y and Z began to repack the rh medium large transport strut. The job went really well. I was the lead technician on duty with rii. So I observed the removal of lower torque link; as well as the installation. I don't recall at this time the position of the washer and apex spacer during the installation of the lower [medium large transport] torque link. The final inspection looked fine as well. Base manager can verify the installation; he was standing there as well. If we did install the washer and apex spacer backwards; I am not sure really how; it does not seem it would have looked correct to me and I would have caught it. But I am human and we were being pressured to get the aircraft out as soon as possible. I reviewed the history of aircraft X and [gear] shimmy seemed to be an issue before the strut repack was accomplished. It may be possible this was installed incorrectly; before we disassembled. Then [again]; may have been second nature [for mechanics] to reinstall the same way they took it apart. Like; I stated above; I honestly don't remember the position of the washer and apex spacer after completion of the installation. I do not believe this caused this incident either.aircraft X had to be towed off runway [after landing] and the whole right medium large transport replaced. [An engineering order] has been issued to perform a fleet check of the apex spacer [position] on all crj-900 medium large transport torque assembly.

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Original NASA ASRS Text

Title: An Inspector and Mechanic report about their involvement with an incorrect position installation of an apex spacer at the right Main Landing Gear (MLG) Torque Links on a CRJ-900 aircraft. The right MLG had wobbled and split in two places on landing.

Narrative: I came in and a CRJ-900; Aircraft X; was Aircraft On Ground (AOG) [status] for parts; for a Right-Hand Main Landing Gear (RH MLG) Strut Repack. We; Mechanics Y and Z and myself (Mechanic X); received the parts into the hangar. Mechanics Y and Z began to repack the RH MLG strut. The job went really well. I was the Lead Technician on duty with RII. So I observed the removal of lower torque link; as well as the installation. I don't recall at this time the position of the washer and apex spacer during the installation of the lower [MLG] torque link. The Final Inspection looked fine as well. Base Manager can verify the installation; he was standing there as well. If we did install the washer and apex spacer backwards; I am not sure really how; it does not seem it would have looked correct to me and I would have caught it. But I am human and we were being pressured to get the aircraft out as soon as possible. I reviewed the history of Aircraft X and [gear] shimmy seemed to be an issue before the strut repack was accomplished. It may be possible this was installed incorrectly; before we disassembled. Then [again]; may have been second nature [for mechanics] to reinstall the same way they took it apart. Like; I stated above; I honestly don't remember the position of the washer and apex spacer after completion of the installation. I do not believe this caused this incident either.Aircraft X had to be towed off runway [after landing] and the whole right MLG replaced. [An Engineering Order] has been issued to perform a Fleet Check of the apex spacer [position] on all CRJ-900 MLG Torque Assembly.

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.