What is one of the key inspections to be performed during a 100-hour inspection?

During a 100-hour inspection, one of the primary focuses is on ensuring that the engine's internal components are functioning properly and efficiently. Checking cylinder compression is a vital part of this inspection, as it directly relates to the engine's performance and the combustion process.

Cylinder compression tests assess the sealing capability of the cylinder and its associated components—such as valves, piston rings, and gaskets. This inspection helps identify any potential issues that could lead to power loss, increased fuel consumption, or mechanical failure. If compression is low in any cylinder, it indicates possible wear or damage that requires further examination or maintenance.

Other inspections, while they are important for overall aircraft maintenance, do not hold the same critical relevance during the 100-hour inspection as checking cylinder compression does. For instance, oil viscosity is essential for engine lubrication but is generally assessed more frequently rather than specifically during the 100-hour inspection. Evaluating battery condition and fuel quality are also important but do not provide as immediate insight into the engine’s operational integrity as a compression test does.