A320
Maintenance Airframe; Maintenance Powerplant
Situational Awareness; Other / Unknown
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors; MEL; Procedure
Following Troubleshooting Manual (TSM) and Aircraft Maintenance Manual (AMM) procedures to determine the cause for brake overheat; I determined that possibly the Anti-Skid System was not managing the brake; which was causing the overheat and not just a temperature reporting error. Maintenance Control agreed with my explanation; allowing the deactivation MEL and subsequent procedure. After retrieving the exact AMM reference for deactivation; I entered it into the maintenance computer; which displayed several subtasks. One of these was a specific procedure for deactivating only the Green [Hydraulic System] NORMAL side. I chose this based on the previous TSM Task for complying with the NORMAL Brake System Tachometer Functional Test. The TSM was referencing only the Green-Normal System with a possible fault. I mistakenly misidentified Green from Yellow [hydraulics]; causing only the Yellow hydraulic line to be stowed for the MEL. Had I removed the correct one [hydraulic line]; the brake would not have activated; even though one side was disconnected and stowed. Since the brake was still active; the high temperature condition recurred upon landing. Since I [had been] working on the NORMAL Braking System; I [had] decided to only deactivate that side; but confused Yellow from Green hydraulic hose couplings. [After landing]; the Green hydraulic line was disconnected and stowed as part of the complete MEL procedure. Please update the MEL reference for the deactivation procedure to read the EXACT subtask [in the maintenance computer] that will link directly to deactivating the entire brake. Currently when this task is entered; several other DEACTIVATION choices appear. Flight delay.
A Line Aircraft Maintenance Technician (AMT) reports he mistakenly mis-identified a Yellow System hydraulic line hose coupling for a Green NORMAL Hydraulic System hose coupling; causing only the Yellow hydraulic line to be stowed for an MEL deferral of an A320 Brake Temperature Indication. High temperature condition recurred due to  brake was still active on landing.