What is a key indication of engine health related to 'smooth running'?

A key indication of engine health is regular power output, as it reflects the engine's ability to operate efficiently and consistently under various conditions. When an engine runs smoothly, it maintains a stable and predictable power output, which is essential for proper aircraft performance. Any significant fluctuations in power can indicate underlying issues such as fuel delivery problems, ignition system failures, or mechanical wear and tear. Consistent power output helps ensure that the engine is functioning optimally, contributing to overall engine reliability and safety during operation.

This aspect of engine health is crucial for pilots and maintenance personnel, as it allows for timely detection of potential problems that could lead to engine failure.