Maintenance Airframe; Maintenance Powerplant
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors
I was assigned to work on a CRJ-700 aircraft that was scheduled for overnight maintenance. I performed a Visual Inspection of the System Number 1 and Number 2 Hydraulic Accumulators and found that they required removal for end cap Non-Destructive Testing (NDT). During Removal and Reinstallation (R/R); I used shop rags to absorb the hydraulic fluid that normally leaks when this task is performed. When finished I did a thorough inspection for tools and materials. All appeared cleared. I asked a Mechanic Y to inspect the Aft Bay before the 311-Door was closed; to 'make sure I didn't leave anything in there.' He performed a Visual Inspection and declared it clear; he then counter-signed all my work cards.Two days later; I was called to the [Maintenance] Office and shown a picture; taken in ZZZ1 of a shop rag jammed in the Rudder Pulley System. I have no explanation of 'why.' Procedures were followed; other employees performed tasks in the Aft Bay. None of them carried shop rags; but they had opportunity to see a rag left behind. No one reported anything and all Performance Testing showed nothing out of the ordinary. I am not certain that I am responsible for this occurrence; but the possibility is there.
I; Mechanic Y; was at ZZZ Hanger having Hydraulic Accumulators One and Two special Detailed Inspection per work cards by Mechanic X. She asked me to give her a counter-signoff in the Aft Equipment Bay to finish the job. I looked up in the Aft Equipment Bay and did not see any FOD. That evening; acting Supervisor showed me a picture of a rag on one of the rudder cables on the same CRJ-700 aircraft. I talked to the Base Manager the following morning about it and that; there is a possibility that the [shop] rag was one of ours and I could have missed it when I counter-signed for the Aft Equipment Bay. The event occurred because I did not see any FOD in the Aft Equipment Bay. [Recommend] be vigilant and look in the unexpected place for FOD.
Two Mechanics were informed that a shop rag was found jammed in the Rudder Pulley System in the Aft Equipment Bay of a CRJ-700 aircraft after they both had signed-off for the area to be free of FOD material.