B737-900
Maintenance Powerplant
Communication Breakdown; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Equipment / Tooling; Human Factors; Manuals; Procedure
While trying to remove N1 fan blade per given Aircraft Maintenance Manual (AMM); tool marks [were] made on [Fan] disk thus requiring unscheduled engine replacement. No exact tooling listed in given AMM to remove N1 Fan blade shim/keeper weights and using hand to work is not really possible. [Recommend] Tool [be] made or listed [in AMM] to remove N1 Fan blade shim/keeper weights and added to AMM 72-21-02 and listed in required tool section. Also; [add maintenance] NOTE: given the importance on not having damage to Fan blade disk due to tooling marks.
An Aircraft Maintenance Technician recommended a specific tool be made or listed in the Aircraft Maintenance Manual for technicians to use to avoid damage to CFM-56 Engine Fan disks when removing the N1 Fan Blade Shim/Keeper weights. Inadvertent tooling damage by Technician required unscheduled engine replacement on a B737-900 aircraft.