Explain the process of deciding between repairing or replacing a damaged turbine NGV.

• A. Always replace NGV without repairing.
• B. Repairs are limited by OEM limits; minor surface damage may be repaired or reworked with coating; cracks or deep wear typically require replacement.
• C. NGVs should be replaced only if the operator requests.
• D. Cost dictates, whichever is cheaper.

Answer: (B)

Deciding between repairing and replacing a damaged turbine NGV relies on whether the damage stays within the manufacturer’s repair limits. If the NGV has only minor surface damage, it can often be repaired or reworked within those limits, and a coating may be applied to restore the surface finish and aerodynamic profile. If cracks, deep wear, or any flaws approach or exceed the OEM repair limits, replacement is required to ensure structural integrity and engine safety. Before making the decision, technicians perform non-destructive testing to verify there are no subsurface defects and to confirm the part remains within allowable tolerances. Replacement is chosen not by cost alone or operator preference, but whenever the damage cannot be safely repaired within approved limits.