Which method is NOT recommended for hand recontouring damaged compressor blades?

The method that is not recommended for hand recontouring damaged compressor blades is the use of large power tools. This method can introduce several problems. Firstly, large power tools can remove material too quickly and inconsistently, leading to a distorted shape of the blade contour. They also generate significant heat during operation, which can affect the integrity of the blade material and lead to unwanted stresses or hardening.

In contrast, hand tools like small files, sanding blocks, and emery cloth allow for more precise control during the recontouring process. These tools enable the technician to carefully shape and smooth the blades without removing excessive material or damaging the underlying structure. A careful hand approach ensures that the aerodynamic characteristics of the compressor blades are maintained, which is crucial for the performance and safety of the engine.