What Borescope Diameter Do I Need?

When There is Not A Clear Choice

Many aircraft have a standard turbine engine such as those models listed above, making the question of “which borescope diameter is right for my application” a less complex one to answer. However, what happens when an MRO facility wants to use their video borescope for more than just a standard turbine inspection? What if they also wish to utilize that same inspection tool for their landing gear and airframe inspections?

That is when diagnosing borescope diameter needs becomes much more in-depth.

If a quality control professional wanted to use a video borescope to check for burrs or slag on a casted part, which diameter would they need? The answer depends not only on the size of the casted part, but also the intricacy of the internal passageways. Some casting forms have tiny insertion points, requiring a borescope with a diameter as slim as 2.8mm (0.11 inches). Other parts are much larger, so a 6.0mm diameter would be a better fit.

A borescope or videoscope must fit in the smallest hole that will be inspected. However, some applications, such as gearbox inspections, call for both large diameter (inspecting the gear teeth) and smaller diameter (checking out bearings) borescopes. In these cases, sometimes purchasing two inspection cameras is the best way to go about confidently completing your quality checks.