Borescope inspection

Borescope inspection is carried out because of the following benefits it can provide in the maintenance program ... 

Figure 21-7 shows the time savings one may obtain by the proper use of borescopic inspection for planned maintenance. 

To facilitate maintenance, gas turbines used for aircraft and those modeled after ffiese have a modular design so that the individual components such as compressor, combustor, and turbine can be taken out of the assembly individually. Those gas turbines allow also for a borescopic inspection of their insides by an optical tube with lens and eyepiece. Heavy industrial gas turbines are not designed for borescopic inspection and must be dismantled for inspection and maintenance. Preventive maintenance is very important for gas turbines. 

In order to overcome apprehension regarding erosion of turbine blades during service and the hazards attending such failure, provision is made for visual inspection by a strobe light and camera while in operation. Scheduled inspection by a camera (borescope) permits... 

Two 1-in., Class 300 borescope connections shall be provided on the inlet casing to inspect the condition of the stator blades and the upstream side of the rotor blades during periods the expander is shut down without disassembly to the expander. 

Visual inspection is a quick and economical method of detecting various types of defects before they cause failure. Its reliability depends upon the ability and experience of the inspector. The inspector must know how to search for critical flaws and how to recognize areas where failure could occur. The human eye is a very discerning instrument, and, with training, the brain can interpret images much better than any automated device can. Visual inspection can be done in many ways, either directly or remotely, by using borescopes, fiberscopes, or video cameras. Visual methods can provide a simple and speedy way to... 

---