What is required when performing an annual or 100-hour inspection on a reciprocating engine aircraft?

The requirement for a cylinder compression check during an annual or 100-hour inspection on a reciprocating engine aircraft is crucial for assessing the health and performance of the engine. This check provides valuable information about the condition of the engine's components, such as valves, piston rings, and cylinder walls, which can affect overall engine efficiency and safety.

Conducting a cylinder compression check involves measuring the compression pressure of each cylinder, which helps identify potential mechanical issues that could lead to engine failure if overlooked. It is a critical diagnostic tool that can reveal problems such as worn piston rings or leaking valves, contributing to informed maintenance decisions.

While visual inspections of the fuselage, fuel system checks, and engine oil changes are also important maintenance tasks, they do not specifically address the internal functioning of the engine in the same direct manner that a cylinder compression check does. Therefore, the necessity of performing this check emphasizes the importance of engine performance in ensuring the safety and reliability of reciprocating engine aircraft during inspections.