Which tool might be used for detecting foreign objects in hard-to-see areas of an aircraft?

A borescope is an essential tool for detecting foreign objects in hard-to-see areas of an aircraft due to its design and functionality. Borescopes are flexible or rigid inspection devices equipped with a small camera and light source, allowing technicians to visualize internal components and concealed spaces without dismantling parts of the aircraft. This capability is particularly useful in aircraft maintenance and inspection, where accessing certain areas can be challenging.

Using a borescope, technicians can carefully examine engines, airframes, and other critical areas for any signs of foreign object debris (FOD), which could potentially lead to serious safety issues. The visual feedback from the borescope allows for effective identification and assessment of any foreign objects that may be present, which is crucial for ensuring the overall safety and integrity of the aircraft.

Other tools listed, such as a multimeter, torque wrench, or pressure gauge, serve different purposes within aeronautical maintenance. A multimeter measures electrical properties, a torque wrench is used to ensure proper fastener tightening, and a pressure gauge monitors fluid levels. None of these tools are designed for inspecting hard-to-reach areas specifically for foreign object detection, which underscores the borescope's unique and critical role in this context.