Gas Turbine Handbook : Principles and Practices

Detectable Problems 191
Figure 12-3. Dual spool gas turbine estimated parameter changes
with low pressure-turbine nozzle area change.
Corrective Action
Geometry changes resulting from oxidation, corrosion, erosion,
or impact damage can be corrected only during overhaul by removal
and replacement of the damaged parts. Depending on the type of
machine this could result in downtime of one day (aero-derivatives) to
several weeks (heavy frame units) 4 . However, certain actions can be
taken to maximize the time between overhaul and to minimize fired