Loose objects often enter an engine's compressor
either accidentally or through carelessness. Thousands
of dollars worth of damage to a compressor rotor can
result from pliers being left in the air intake, as shown
in figure 10-1. The nut and bolt holding the pliers
together came loose and went through the compressor,
causing the damage shown in the illustration. A simple
solution to the problem of tools drawn into an engine is
to check the tools against a tool checklist.
Internal mechanical failures, such as a compressor
blade breaking off, result in compressor efficiency loss.
These failures are difficult to detect. Broken blades and
vanes result in high exhaust gas temperatures or an
increase in compressor rpm due to loss of efficiency. Of
course, mechanical failures of compressor blades could
result in severe damage to the compressor, combustion
chamber, and the turbine as foreign object damage
Compressor Blade Damage
Figure 10-2.-(A) Blade showing dent and galling;
(B) blade showing a score; (C) blade showing
Defining and showing examples of damage may help
scratches; (D) blade showing gouge and burr.
you to recognize damage and make
Figure 10-3.-(A) Blade showing corrosion
(pitting); (B) blade showing cracks; (C) blade
Figure 10-1.-Compressor damage caused by
showing burn; (D) blade showing damage and
pliers passing through compressor.