Which of the following is NOT a part of engine failure indicators during a FEVER check?

The identification of engine failure indicators is crucial for pilot safety and effective aircraft operation. During a FEVER check, pilots evaluate various symptoms that suggest engine performance issues.

Battery voltage levels are not included in the engine failure indicator list because they pertain more to the electrical system of the aircraft rather than the engine's operational status. While a loss of battery power can impact overall aircraft functionality, it does not provide direct information concerning engine performance or failure.

In contrast, fluctuating fuel flow, erratic engine operations, and roughness of engine sounds are all direct indicators of potential engine failure. Fluctuating fuel flow can indicate inconsistencies in fuel delivery, erratic engine operations can suggest issues with the engine's internal mechanisms, and rough sounds may signal problems within the engine itself. These symptoms are critical for pilots to recognize and react to in order to maintain safe operation of the aircraft.