In modern Endoscopy, fiberscopes are used to inspect critical areas otherwise invisible to the naked eye due to lack of access without incurring costly & lengthily dismantling.
A bundle of fibre optics, combined with a light source, enable the operator to view areas such as machinery internal works, shaft tubes, tank interiors, etc. on an LCD screen.

By connecting a digital camera to the fiberscope high-resolution colour images and video can be recorded.

Mechanical
Internal engine parts.
Internal gearbox parts.

General
Internal inspections of tanks & pipes.
Internal inspections of shaft tubes &
Inspections of any other hard-to-reach areas (hull structures, mast & spars, etc).

There are some limitations due the nature of the Fiberscope. Viewing angle is limited as is the maximum reachable length, and a Ø8mm wide channel is required as a minimum in order to reach its destination.