Maintenance Airframe; Maintenance Powerplant
Situational Awareness; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Aircraft; Procedure
THSA (Trimmable Horizontal Stabilizer Assembly) Master Spline threaded bushing    (G1) was found missing safety wire during unrelated THSA general visual inspection. See AMM 27-44-00-710-001-A for safety wire installation requirements and Figure 27-44-00-991-00300-A test procedure of jamming simulation tool: Sheet 1. See log page XXXXXXX. This safety wire is removed and installed during THSA jamming tests; usually scheduled with some A checks. There is an  inspection of the installed safety wire on the task card.
A320 technician reported required safety wire missing on THSA master spline threaded bushing discovered during an unrelated general visual inspection.