Regional Jet 900 (CRJ900)
Maintenance Airframe; Maintenance Powerplant
Workload; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors
Aircraft was written up for a right main strut leak. I took the call with a co-worker who acted the inspector for the task. We performed the maintenance required following the Maintenance Manual.I have since learned that a brake line failure or fitting failed causing a brake to lock-up a few flights later and may be related to the maintenance I performed that night. While I don't recall the specifics of the task I do recall the operational and leak checks related to the strut and brake installation.As of right now I'm unsure of how this could have happened. I do my best to check and double-check my work. Since the failure occurred in the scope of my work I can't help but feel responsible.
Another mechanic and I went to an aircraft that had the right strut leaking hydraulic fluid. We removed the lower half of the strut; replaced the bad seals; reinstalled the lower half of the strut and put everything back together. Including the brakes and tires; we installed all the hydraulic lines; checked for security of fittings on the brakes; and checked the brakes for operation and leaks. The brakes had no leaks and the brakes worked normal; so after that we serviced the strut with 5606 and nitrogen; did our paper work and signed it off an went back to home base. I was notified later; that a couple days ago that one of the brakes locked up and they found one of quick disconnect fittings had backed off causing the brake to lock up.I do not know why it happened. I feel that we did not do anything wrong on the maintenance that we did; maybe the quick disconnect were getting weak and worked its way loose.Maybe the quick disconnect fittings should be inspected and replaced if bad during C checks.
The brakes locked up when landing because a hydraulic line failed. Two days prior maintenance was accomplished on the same landing gear and brake system.