Borescope

A borescope is a rigid tube with an eyepiece on one end and an imaging lens on the other. It is used for inspection work. It is similar to a fiberscope, but it is not flexible, and is therefore better suited to certain tasks such as gunsmithing. Like a fiberscope, it may be fitted with a magnifying device and a way to illuminate the work being inspected, and the eyepiece may be replaced by an imaging device such as a CCD camera.

Contrast endoscope

Borescopes are used in the visual inspection of aircraft engines. These require particular attention because of safety requirements.

Usually a fiberoptic flexible borescope is used to access combustion chamber or " Burner Cans" in order to view the condition of the compressed air inlets, turbine blades and seals without disassembling the engine.

Criteria for such an instrument is usually clarity of the fiberoptic image guide, level of light transmitted by the fiberoptic lightguides, quality of the sheathing and articulation mechanism components ratio of articulation, magnification power of the lenses, the field of view anf the angles of view.

Fiber content is also critical to provide the highest possible resolution to the viewer. Minimal quantity is 10,000 pixels and higher to 22,000 approximately in the larger diameter borescopes.